微软官方的SQLHelper类(含完整中文注释) 【转】

微软官方的SQLHelper类(含完整中文注释) 【转 https://blog.csdn.net/zuoyefeng1990/article/details/62222886】
using System;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.Collections;
namespace myhelper
{

/// <summary>
/// SqlServer数据访问帮助类
/// </summary>
public sealed class SqlHelper
{
    #region 私有构造函数和方法
    private SqlHelper() {}
    /// <summary>
    /// 将SqlParameter参数数组(参数值)分配给SqlCommand命令.
    /// 这个方法将给任何一个参数分配DBNull.Value;
    /// 该操作将阻止默认值的使用.
    /// </summary>SqlHelperSqlHelper
    /// <param>命令名</param>
    /// <param>SqlParameters数组</param>
    private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
    {
        if( command == null ) throw new ArgumentNullException( "command" );
        if( commandParameters != null )
        {
            foreach (SqlParameter p in commandParameters)
            {
                if( p != null )
                {
                    // 检查未分配值的输出参数,将其分配以DBNull.Value.
                    if ( ( p.Direction == ParameterDirection.InputOutput || p.Direction == ParameterDirection.Input ) && 
                        (p.Value == null))
                    {
                        p.Value = DBNull.Value;
                    }
                    command.Parameters.Add(p);
                }
            }
        }
    }
    
    /// <summary>
    /// 将DataRow类型的列值分配到SqlParameter参数数组.
    /// </summary>
    /// <param>要分配值的SqlParameter参数数组</param>
    /// <param>将要分配给存储过程参数的DataRow</param>
    private static void AssignParameterValues(SqlParameter[] commandParameters, DataRow dataRow)
    {
        if ((commandParameters == null) || (dataRow == null)) 
        {
            return;
        }
        int i = 0;
        // 设置参数值
        foreach(SqlParameter commandParameter in commandParameters)
        {
            // 创建参数名称,如果不存在,只抛出一个异常.
            if( commandParameter.ParameterName == null || 
                commandParameter.ParameterName.Length <= 1 )
                throw new Exception( 
                    string.Format("请提供参数{0}一个有效的名称{1}.", i, commandParameter.ParameterName ) );
            // 从dataRow的表中获取为参数数组中数组名称的列的索引.
            // 如果存在和参数名称相同的列,则将列值赋给当前名称的参数.
            if (dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring(1)) != -1)
                commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];
            i++;
        }
    }
    
    /// <summary>
    /// 将一个对象数组分配给SqlParameter参数数组.
    /// </summary>
    /// <param>要分配值的SqlParameter参数数组</param>
    /// <param>将要分配给存储过程参数的对象数组</param>
    private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues)
    {
        if ((commandParameters == null) || (parameterValues == null)) 
        {
            return;
        }
        // 确保对象数组个数与参数个数匹配,如果不匹配,抛出一个异常.
        if (commandParameters.Length != parameterValues.Length)
        {
            throw new ArgumentException("参数值个数与参数不匹配.");
        }
        // 给参数赋值
        for (int i = 0, j = commandParameters.Length; i < j; i++)
        {
            // If the current array value derives from IDbDataParameter, then assign its Value property
            if (parameterValues is IDbDataParameter)
            {
                IDbDataParameter paramInstance = (IDbDataParameter)parameterValues;
                if( paramInstance.Value == null )
                {
                    commandParameters.Value = DBNull.Value; 
                }
                else
                {
                    commandParameters.Value = paramInstance.Value;
                }
            }
            else if (parameterValues == null)
            {
                commandParameters.Value = DBNull.Value;
            }
            else
            {
                commandParameters.Value = parameterValues;
            }
        }
    }
    
    /// <summary>
    /// 预处理用户提供的命令,数据库连接/事务/命令类型/参数
    /// </summary>
    /// <param>要处理的SqlCommand</param>
    /// <param>数据库连接</param>
    /// <param>一个有效的事务或者是null值</param>
    /// <param>命令类型 (存储过程,命令文本, 其它.)</param>
    /// <param>存储过程名或都T-SQL命令文本</param>
    /// <param>和命令相关联的SqlParameter参数数组,如果没有参数为'null'</param>
    /// <param><c>true</c> 如果连接是打开的,则为true,其它情况下为false.</param>
    private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, out bool mustCloseConnection )
    {
        if( command == null ) throw new ArgumentNullException( "command" );
        if( commandText == null || commandText.Length == 0 ) throw new ArgumentNullException( "commandText" );
        // If the provided connection is not open, we will open it
        if (connection.State != ConnectionState.Open)
        {
            mustCloseConnection = true;
            connection.Open();
        }
        else
        {
            mustCloseConnection = false;
        }
        // 给命令分配一个数据库连接.
        command.Connection = connection;
        // 设置命令文本(存储过程名或SQL语句)
        command.CommandText = commandText;
        // 分配事务
        if (transaction != null)
        {
            if( transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
            command.Transaction = transaction;
        }
        // 设置命令类型.
        command.CommandType = commandType;
        // 分配命令参数
        if (commandParameters != null)
        {
            AttachParameters(command, commandParameters);
        }
        return;
    }
    #endregion 私有构造函数和方法结束
        
    #region ExecuteNonQuery命令
    /// <summary>
    /// 执行指定连接字符串,类型的SqlCommand.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本, 其它.)</param>
    /// <param>存储过程名称或SQL语句</param>
    /// <returns>返回命令影响的行数</returns>
    public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
    {
        return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定连接字符串,类型的SqlCommand.如果没有提供参数,不返回结果.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本, 其它.)</param>
    /// <param>存储过程名称或SQL语句</param>
    /// <param>SqlParameter参数数组</param>
    /// <returns>返回命令影响的行数</returns>
    public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            return ExecuteNonQuery(connection, commandType, commandText, commandParameters);
        }
    }
    
    /// <summary>
    /// 执行指定连接字符串的存储过程,将对象数组的值赋给存储过程参数,
    /// 此方法需要在参数缓存方法中探索参数并生成参数.
    /// </summary>
    /// <remarks>
    /// 这个方法没有提供访问输出参数和返回值.
    /// 示例:  
    ///  int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接字符串/param>
    /// <param>存储过程名称</param>
    /// <param>分配到存储过程输入参数的对象数组</param>
    /// <returns>返回受影响的行数</returns>
    public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果存在参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从探索存储过程参数(加载到缓存)并分配给存储过程参数数组.
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            // 没有参数情况下
            return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令 
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型(存储过程,命令文本或其它.)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <returns>返回影响的行数</returns>
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
    {
        return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型(存储过程,命令文本或其它.)</param>
    /// <param>T存储过程名称或T-SQL语句</param>
    /// <param>SqlParamter参数数组</param>
    /// <returns>返回影响的行数</returns>
    public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {    
        if( connection == null ) throw new ArgumentNullException( "connection" );
        // 创建SqlCommand命令,并进行预处理
        SqlCommand cmd = new SqlCommand();
        bool mustCloseConnection = false;
        PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
        
        // Finally, execute the command
        int retval = cmd.ExecuteNonQuery();
        
        // 清除参数,以便再次使用.
        cmd.Parameters.Clear();
        if( mustCloseConnection )
            connection.Close();
        return retval;
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,将对象数组的值赋给存储过程参数.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值
    /// 示例:  
    ///  int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回影响的行数</returns>
    public static int ExecuteNonQuery(SqlConnection connection, string spName, params object[] parameterValues)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            // 给存储过程分配参数值
            AssignParameterValues(commandParameters, parameterValues);
            return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行带事务的SqlCommand.
    /// </summary>
    /// <remarks>
    /// 示例.:  
    ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型(存储过程,命令文本或其它.)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <returns>返回影响的行数/returns>
    public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText)
    {
        return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行带事务的SqlCommand(指定参数).
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型(存储过程,命令文本或其它.)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>SqlParamter参数数组</param>
    /// <returns>返回影响的行数</returns>
    public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        // 预处理
        SqlCommand cmd = new SqlCommand();
        bool mustCloseConnection = false;
        PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
            
        // 执行
        int retval = cmd.ExecuteNonQuery();
            
        // 清除参数集,以便再次使用.
        cmd.Parameters.Clear();
        return retval;
    }
    
    /// <summary>
    /// 执行带事务的SqlCommand(指定参数值).
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值
    /// 示例:  
    ///  int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回受影响的行数</returns>
    public static int ExecuteNonQuery(SqlTransaction transaction, string spName, params object[] parameterValues)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            // 调用重载方法
            return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            // 没有参数值
            return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion ExecuteNonQuery方法结束
        
    #region ExecuteDataset方法
    /// <summary>
    /// 执行指定数据库连接字符串的命令,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
    {
        return ExecuteDataset(connectionString, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的命令,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 示例: 
    ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>SqlParamters参数数组</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        // 创建并打开数据库连接对象,操作完成释放对象.
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            // 调用指定数据库连接字符串重载方法.
            return ExecuteDataset(connection, commandType, commandText, commandParameters);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的命令,直接提供参数值,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值.
    /// 示例: 
    ///  DataSet ds = ExecuteDataset(connString, "GetOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中检索存储过程参数
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
            // 给存储过程参数分配值
            AssignParameterValues(commandParameters, parameterValues);
            return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名或T-SQL语句</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText)
    {
        return ExecuteDataset(connection, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,指定存储过程参数,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名或T-SQL语句</param>
    /// <param>SqlParamter参数数组</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        // 预处理
        SqlCommand cmd = new SqlCommand();
        bool mustCloseConnection = false;
        PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
            
        // 创建SqlDataAdapter和DataSet.
        using( SqlDataAdapter da = new SqlDataAdapter(cmd) )
        {
            DataSet ds = new DataSet();
            // 填充DataSet.
            da.Fill(ds);
            
            cmd.Parameters.Clear();
            if( mustCloseConnection )
                connection.Close();
            return ds;
        }    
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,指定参数值,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输入参数和返回值.
    /// 示例.:  
    ///  DataSet ds = ExecuteDataset(conn, "GetOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(SqlConnection connection, string spName, params object[] parameterValues)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 比缓存中加载存储过程参数
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            // 给存储过程参数分配值
            AssignParameterValues(commandParameters, parameterValues);
            return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定事务的命令,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param>事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名或T-SQL语句</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText)
    {
        return ExecuteDataset(transaction, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定事务的命令,指定参数,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名或T-SQL语句</param>
    /// <param>SqlParamter参数数组</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        // 预处理
        SqlCommand cmd = new SqlCommand();
        bool mustCloseConnection = false;
        PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
            
        // 创建 DataAdapter & DataSet
        using( SqlDataAdapter da = new SqlDataAdapter(cmd) )
        {
            DataSet ds = new DataSet();
            da.Fill(ds);
            cmd.Parameters.Clear();
            return ds;
        }    
    }
    
    /// <summary>
    /// 执行指定事务的命令,指定参数值,返回DataSet.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输入参数和返回值.
    /// 示例.:  
    ///  DataSet ds = ExecuteDataset(trans, "GetOrders", 24, 36);
    /// </remarks>
    /// <param>事务</param>
    /// <param>存储过程名</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回一个包含结果集的DataSet</returns>
    public static DataSet ExecuteDataset(SqlTransaction transaction, string spName, params object[] parameterValues)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            // 给存储过程参数分配值
            AssignParameterValues(commandParameters, parameterValues);
            return ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion ExecuteDataset数据集命令结束
    
    #region ExecuteReader 数据阅读器
    /// <summary>
    /// 枚举,标识数据库连接是由SqlHelper提供还是由调用者提供
    /// </summary>
    private enum SqlConnectionOwnership    
    {
        /// <summary>由SqlHelper提供连接</summary>
        Internal, 
        /// <summary>由调用者提供连接</summary>
        External
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的数据阅读器.
    /// </summary>
    /// <remarks>
    /// 如果是SqlHelper打开连接,当连接关闭DataReader也将关闭.
    /// 如果是调用都打开连接,DataReader由调用都管理.
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>一个有效的事务,或者为 'null'</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名或T-SQL语句</param>
    /// <param>SqlParameters参数数组,如果没有参数则为'null'</param>
    /// <param>标识数据库连接对象是由调用者提供还是由SqlHelper提供</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    private static SqlDataReader ExecuteReader(SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, SqlConnectionOwnership connectionOwnership)
    {    
        if( connection == null ) throw new ArgumentNullException( "connection" );
        bool mustCloseConnection = false;
        // 创建命令
        SqlCommand cmd = new SqlCommand();
        try
        {
            PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
        
            // 创建数据阅读器
            SqlDataReader dataReader;
            if (connectionOwnership == SqlConnectionOwnership.External)
            {
                dataReader = cmd.ExecuteReader();
            }
            else
            {
                dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
        
            // 清除参数,以便再次使用..
            // HACK: There is a problem here, the output parameter values are fletched 
            // when the reader is closed, so if the parameters are detached from the command
            // then the SqlReader can磘 set its values. 
            // When this happen, the parameters can磘 be used again in other command.
            bool canClear = true;
            foreach(SqlParameter commandParameter in cmd.Parameters)
            {
                if (commandParameter.Direction != ParameterDirection.Input)
                    canClear = false;
            }
        
            if (canClear)
            {
                cmd.Parameters.Clear();
            }
            return dataReader;
        }
        catch
        {
            if( mustCloseConnection )
                connection.Close();
            throw;
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的数据阅读器.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名或T-SQL语句</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
    {
        return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的数据阅读器,指定参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名或T-SQL语句</param>
    /// <param>SqlParamter参数数组(new SqlParameter("@prodid", 24))</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        SqlConnection connection = null;
        try
        {
            connection = new SqlConnection(connectionString);
            connection.Open();
            return ExecuteReader(connection, null, commandType, commandText, commandParameters,SqlConnectionOwnership.Internal);
        }
        catch
        {
            // If we fail to return the SqlDatReader, we need to close the connection ourselves
            if( connection != null ) connection.Close();
            throw;
        }
        
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的数据阅读器,指定参数值.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 示例:  
    ///  SqlDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
            AssignParameterValues(commandParameters, parameterValues);
            return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的数据阅读器.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名或T-SQL语句</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText)
    {
        return ExecuteReader(connection, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// [调用者方式]执行指定数据库连接对象的数据阅读器,指定参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>SqlParamter参数数组</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        return ExecuteReader(connection, (SqlTransaction)null, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
    }
    
    /// <summary>
    /// [调用者方式]执行指定数据库连接对象的数据阅读器,指定参数值.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 示例:  
    ///  SqlDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>T存储过程名</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(SqlConnection connection, string spName, params object[] parameterValues)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            AssignParameterValues(commandParameters, parameterValues);
            return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            return ExecuteReader(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数值.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText)
    {
        return ExecuteReader(transaction, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///   SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
    }
    
    /// <summary>
    /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数值.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  SqlDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>存储过程名称</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReader(SqlTransaction transaction, string spName, params object[] parameterValues)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            AssignParameterValues(commandParameters, parameterValues);
            return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            // 没有参数值
            return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion ExecuteReader数据阅读器
        
    #region ExecuteScalar 返回结果集中的第一行第一列        
    /// <summary>
    /// 执行指定数据库连接字符串的命令,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
    {
        // 执行参数为空的方法
        return ExecuteScalar(connectionString, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的命令,指定参数,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        // 创建并打开数据库连接对象,操作完成释放对象.
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            // 调用指定数据库连接字符串重载方法.
            return ExecuteScalar(connection, commandType, commandText, commandParameters);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的命令,指定参数值,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名称</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            // 调用重载方法
            return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            // 没有参数值
            return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText)
    {
        // 执行参数为空的方法
        return ExecuteScalar(connection, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,指定参数,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        // 创建SqlCommand命令,并进行预处理
        SqlCommand cmd = new SqlCommand();
        bool mustCloseConnection = false;
        PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
            
        // 执行SqlCommand命令,并返回结果.
        object retval = cmd.ExecuteScalar();
            
        // 清除参数,以便再次使用.
        cmd.Parameters.Clear();
        if( mustCloseConnection )
            connection.Close();
        return retval;
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,指定参数值,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(conn, "GetOrderCount", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(SqlConnection connection, string spName, params object[] parameterValues)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            // 调用重载方法
            return ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            // 没有参数值
            return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定数据库事务的命令,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText)
    {
        // 执行参数为空的方法
        return ExecuteScalar(transaction, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库事务的命令,指定参数,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        // 创建SqlCommand命令,并进行预处理
        SqlCommand cmd = new SqlCommand();
        bool mustCloseConnection = false;
        PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
            
        // 执行SqlCommand命令,并返回结果.
        object retval = cmd.ExecuteScalar();
            
        // 清除参数,以便再次使用.
        cmd.Parameters.Clear();
        return retval;
    }
    
    /// <summary>
    /// 执行指定数据库事务的命令,指定参数值,返回结果集中的第一行第一列.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  int orderCount = (int)ExecuteScalar(trans, "GetOrderCount", 24, 36);
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>存储过程名称</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalar(SqlTransaction transaction, string spName, params object[] parameterValues)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // PPull the parameters for this stored procedure from the parameter cache ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            // 调用重载方法
            return ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            // 没有参数值
            return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion ExecuteScalar 
           
    #region ExecuteXmlReader XML阅读器
    /// <summary>
    /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
    /// <returns>返回XmlReader结果集对象.</returns>
    public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText)
    {
        // 执行参数为空的方法
        return ExecuteXmlReader(connection, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    /// <returns>返回XmlReader结果集对象.</returns>
    public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        bool mustCloseConnection = false;
        // 创建SqlCommand命令,并进行预处理
        SqlCommand cmd = new SqlCommand();
        try
        {
            PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
        
            // 执行命令
            XmlReader retval = cmd.ExecuteXmlReader();
        
            // 清除参数,以便再次使用.
            cmd.Parameters.Clear();
            return retval;
        }
        catch
        {    
            if( mustCloseConnection )
                connection.Close();
            throw;
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数值.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  XmlReader r = ExecuteXmlReader(conn, "GetOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称 using "FOR XML AUTO"</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回XmlReader结果集对象.</returns>
    public static XmlReader ExecuteXmlReader(SqlConnection connection, string spName, params object[] parameterValues)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            // 调用重载方法
            return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            // 没有参数值
            return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders");
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
    /// <returns>返回XmlReader结果集对象.</returns>
    public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText)
    {
        // 执行参数为空的方法
        return ExecuteXmlReader(transaction, commandType, commandText, (SqlParameter[])null);
    }
    
    /// <summary>
    /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    /// <returns>返回XmlReader结果集对象.</returns>
    public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        // 创建SqlCommand命令,并进行预处理
        SqlCommand cmd = new SqlCommand();
        bool mustCloseConnection = false;
        PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
        
        // 执行命令
        XmlReader retval = cmd.ExecuteXmlReader();
        
        // 清除参数,以便再次使用.
        cmd.Parameters.Clear();
        return retval;            
    }
    
    /// <summary>
    /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数值.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  XmlReader r = ExecuteXmlReader(trans, "GetOrders", 24, 36);
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>存储过程名称</param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    /// <returns>返回一个包含结果集的DataSet.</returns>
    public static XmlReader ExecuteXmlReader(SqlTransaction transaction, string spName, params object[] parameterValues)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            // 调用重载方法
            return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else 
        {
            // 没有参数值
            return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion ExecuteXmlReader 阅读器结束
        
    #region FillDataset 填充数据集
    /// <summary>
    /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)</param>
    public static void FillDataset(string connectionString, CommandType commandType, string commandText, DataSet dataSet, string[] tableNames)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
        
        // 创建并打开数据库连接对象,操作完成释放对象.
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            // 调用指定数据库连接字符串重载方法.
            FillDataset(connection, commandType, commandText, dataSet, tableNames);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集.指定命令参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>
    public static void FillDataset(string connectionString, CommandType commandType,
        string commandText, DataSet dataSet, string[] tableNames,
        params SqlParameter[] commandParameters)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
        // 创建并打开数据库连接对象,操作完成释放对象.
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            // 调用指定数据库连接字符串重载方法.
            FillDataset(connection, commandType, commandText, dataSet, tableNames, commandParameters);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集,指定存储过程参数值.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, 24);
    /// </remarks>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名称</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>    
    /// <param>分配给存储过程输入参数的对象数组</param>
    public static void FillDataset(string connectionString, string spName,
        DataSet dataSet, string[] tableNames,
        params object[] parameterValues)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
        // 创建并打开数据库连接对象,操作完成释放对象.
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            // 调用指定数据库连接字符串重载方法.
            FillDataset (connection, spName, dataSet, tableNames, parameterValues);
        }
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,映射数据表并填充数据集.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>    
    public static void FillDataset(SqlConnection connection, CommandType commandType, 
        string commandText, DataSet dataSet, string[] tableNames)
    {
        FillDataset(connection, commandType, commandText, dataSet, tableNames, null);
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,映射数据表并填充数据集,指定参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    public static void FillDataset(SqlConnection connection, CommandType commandType, 
        string commandText, DataSet dataSet, string[] tableNames,
        params SqlParameter[] commandParameters)
    {
        FillDataset(connection, null, commandType, commandText, dataSet, tableNames, commandParameters);
    }
    
    /// <summary>
    /// 执行指定数据库连接对象的命令,映射数据表并填充数据集,指定存储过程参数值.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  FillDataset(conn, "GetOrders", ds, new string[] {"orders"}, 24, 36);
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    public static void FillDataset(SqlConnection connection, string spName, 
        DataSet dataSet, string[] tableNames,
        params object[] parameterValues)
    {
        if ( connection == null ) throw new ArgumentNullException( "connection" );
        if (dataSet == null ) throw new ArgumentNullException( "dataSet" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            // 调用重载方法
            FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
        }
        else 
        {
            // 没有参数值
            FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames);
        }    
    }
    
    /// <summary>
    /// 执行指定数据库事务的命令,映射数据表并填充数据集.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>
    public static void FillDataset(SqlTransaction transaction, CommandType commandType, 
        string commandText,
        DataSet dataSet, string[] tableNames)
    {
        FillDataset (transaction, commandType, commandText, dataSet, tableNames, null);    
    }
    
    /// <summary>
    /// 执行指定数据库事务的命令,映射数据表并填充数据集,指定参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    public static void FillDataset(SqlTransaction transaction, CommandType commandType, 
        string commandText, DataSet dataSet, string[] tableNames,
        params SqlParameter[] commandParameters)
    {
        FillDataset(transaction.Connection, transaction, commandType, commandText, dataSet, tableNames, commandParameters);
    }
    
    /// <summary>
    /// 执行指定数据库事务的命令,映射数据表并填充数据集,指定存储过程参数值.
    /// </summary>
    /// <remarks>
    /// 此方法不提供访问存储过程输出参数和返回值参数.
    /// 
    /// 示例:  
    ///  FillDataset(trans, "GetOrders", ds, new string[]{"orders"}, 24, 36);
    /// </remarks>
    /// <param>一个有效的连接事务</param>
    /// <param>存储过程名称</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>
    /// <param>分配给存储过程输入参数的对象数组</param>
    public static void FillDataset(SqlTransaction transaction, string spName,
        DataSet dataSet, string[] tableNames,
        params object[] parameterValues) 
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果有参数值
        if ((parameterValues != null) && (parameterValues.Length > 0)) 
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            // 给存储过程参数赋值
            AssignParameterValues(commandParameters, parameterValues);
            // 调用重载方法
            FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
        }
        else 
        {
            // 没有参数值
            FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames);
        }    
    }
    
    /// <summary>
    /// [私有方法][内部调用]执行指定数据库连接对象/事务的命令,映射数据表并填充数据集,DataSet/TableNames/SqlParameters.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  FillDataset(conn, trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>一个有效的连接事务</param>
    /// <param>命令类型 (存储过程,命令文本或其它)</param>
    /// <param>存储过程名称或T-SQL语句</param>
    /// <param>要填充结果集的DataSet实例</param>
    /// <param>表映射的数据表数组
    /// 用户定义的表名 (可有是实际的表名.)
    /// </param>
    /// <param>分配给命令的SqlParamter参数数组</param>
    private static void FillDataset(SqlConnection connection, SqlTransaction transaction, CommandType commandType, 
        string commandText, DataSet dataSet, string[] tableNames,
        params SqlParameter[] commandParameters)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( dataSet == null ) throw new ArgumentNullException( "dataSet" );
        // 创建SqlCommand命令,并进行预处理
        SqlCommand command = new SqlCommand();
        bool mustCloseConnection = false;
        PrepareCommand(command, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection );
            
        // 执行命令
        using( SqlDataAdapter dataAdapter = new SqlDataAdapter(command) )
        {
            
            // 追加表映射
            if (tableNames != null && tableNames.Length > 0)
            {
                string tableName = "Table";
                for (int index=0; index < tableNames.Length; index++)
                {
                    if( tableNames[index] == null || tableNames[index].Length == 0 ) throw new ArgumentException( "The tableNames parameter must contain a list of tables, a value was provided as null or empty string.", "tableNames" );
                    dataAdapter.TableMappings.Add(tableName, tableNames[index]);
                    tableName += (index + 1).ToString();
                }
            }
            
            // 填充数据集使用默认表名称
            dataAdapter.Fill(dataSet);
            // 清除参数,以便再次使用.
            command.Parameters.Clear();
        }
        if( mustCloseConnection )
            connection.Close();
    }
    #endregion
    
    #region UpdateDataset 更新数据集
    /// <summary>
    /// 执行数据集更新到数据库,指定inserted, updated, or deleted命令.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  UpdateDataset(conn, insertCommand, deleteCommand, updateCommand, dataSet, "Order");
    /// </remarks>
    /// <param>[追加记录]一个有效的T-SQL语句或存储过程</param>
    /// <param>[删除记录]一个有效的T-SQL语句或存储过程</param>
    /// <param>[更新记录]一个有效的T-SQL语句或存储过程</param>
    /// <param>要更新到数据库的DataSet</param>
    /// <param>要更新到数据库的DataTable</param>
    public static void UpdateDataset(SqlCommand insertCommand, SqlCommand deleteCommand, SqlCommand updateCommand, DataSet dataSet, string tableName)
    {
        if( insertCommand == null ) throw new ArgumentNullException( "insertCommand" );
        if( deleteCommand == null ) throw new ArgumentNullException( "deleteCommand" );
        if( updateCommand == null ) throw new ArgumentNullException( "updateCommand" );
        if( tableName == null || tableName.Length == 0 ) throw new ArgumentNullException( "tableName" ); 
        // 创建SqlDataAdapter,当操作完成后释放.
        using (SqlDataAdapter dataAdapter = new SqlDataAdapter())
        {
            // 设置数据适配器命令
            dataAdapter.UpdateCommand = updateCommand;
            dataAdapter.InsertCommand = insertCommand;
            dataAdapter.DeleteCommand = deleteCommand;
            // 更新数据集改变到数据库
            dataAdapter.Update (dataSet, tableName); 
            // 提交所有改变到数据集.
            dataSet.AcceptChanges();
        }
    }
    #endregion
        
    #region CreateCommand 创建一条SqlCommand命令
    /// <summary>
    /// 创建SqlCommand命令,指定数据库连接对象,存储过程名和参数.
    /// </summary>
    /// <remarks>
    /// 示例:  
    ///  SqlCommand command = CreateCommand(conn, "AddCustomer", "CustomerID", "CustomerName");
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称</param>
    /// <param>源表的列名称数组</param>
    /// <returns>返回SqlCommand命令</returns>
    public static SqlCommand CreateCommand(SqlConnection connection, string spName, params string[] sourceColumns) 
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 创建命令
        SqlCommand cmd = new SqlCommand( spName, connection );
        cmd.CommandType = CommandType.StoredProcedure;
        // 如果有参数值
        if ((sourceColumns != null) && (sourceColumns.Length > 0)) 
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            // 将源表的列到映射到DataSet命令中.
            for (int index=0; index < sourceColumns.Length; index++)
                commandParameters[index].SourceColumn = sourceColumns[index];
            // Attach the discovered parameters to the SqlCommand object
            AttachParameters (cmd, commandParameters);
        }
        return cmd;
    }
    #endregion
        
    #region ExecuteNonQueryTypedParams 类型化参数(DataRow)
    /// <summary>
    /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回受影响的行数.
    /// </summary>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回影响的行数</returns>
    public static int ExecuteNonQueryTypedParams(String connectionString, String spName, DataRow dataRow)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        
        // 如果row有值,存储过程必须初始化.
        if (dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
                            
            return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回受影响的行数.
    /// </summary>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回影响的行数</returns>
    public static int ExecuteNonQueryTypedParams(SqlConnection connection, String spName, DataRow dataRow)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if (dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
                            
            return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定连接数据库事物的存储过程,使用DataRow做为参数值,返回受影响的行数.
    /// </summary>
    /// <param>一个有效的连接事务 object</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回影响的行数</returns>
    public static int ExecuteNonQueryTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // Sf the row has values, the store procedure parameters must be initialized
        if (dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
                            
            return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion
        
    #region ExecuteDatasetTypedParams 类型化参数(DataRow)
    /// <summary>
    /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回DataSet.
    /// </summary>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回一个包含结果集的DataSet.</returns>
    public static DataSet ExecuteDatasetTypedParams(string connectionString, String spName, DataRow dataRow)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        //如果row有值,存储过程必须初始化.
        if ( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回DataSet.
    /// </summary>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回一个包含结果集的DataSet.</returns>
    /// 
    public static DataSet ExecuteDatasetTypedParams(SqlConnection connection, String spName, DataRow dataRow)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回DataSet.
    /// </summary>
    /// <param>一个有效的连接事务 object</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回一个包含结果集的DataSet.</returns>
    public static DataSet ExecuteDatasetTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion
        
    #region ExecuteReaderTypedParams 类型化参数(DataRow)
    /// <summary>
    /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回DataReader.
    /// </summary>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReaderTypedParams(String connectionString, String spName, DataRow dataRow)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        
        // 如果row有值,存储过程必须初始化.
        if ( dataRow != null && dataRow.ItemArray.Length > 0 )
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
        }
    }
            
    /// <summary>
    /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回DataReader.
    /// </summary>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReaderTypedParams(SqlConnection connection, String spName, DataRow dataRow)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定连接数据库事物的存储过程,使用DataRow做为参数值,返回DataReader.
    /// </summary>
    /// <param>一个有效的连接事务 object</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回包含结果集的SqlDataReader</returns>
    public static SqlDataReader ExecuteReaderTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0 )
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion
        
    #region ExecuteScalarTypedParams 类型化参数(DataRow)
    /// <summary>
    /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
    /// </summary>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalarTypedParams(String connectionString, String spName, DataRow dataRow)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
    /// </summary>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalarTypedParams(SqlConnection connection, String spName, DataRow dataRow)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
    /// </summary>
    /// <param>一个有效的连接事务 object</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回结果集中的第一行第一列</returns>
    public static object ExecuteScalarTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion
        
    #region ExecuteXmlReaderTypedParams 类型化参数(DataRow)
    /// <summary>
    /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回XmlReader类型的结果集.
    /// </summary>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回XmlReader结果集对象.</returns>
    public static XmlReader ExecuteXmlReaderTypedParams(SqlConnection connection, String spName, DataRow dataRow)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
        }
    }
    
    /// <summary>
    /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回XmlReader类型的结果集.
    /// </summary>
    /// <param>一个有效的连接事务 object</param>
    /// <param>存储过程名称</param>
    /// <param>使用DataRow作为参数值</param>
    /// <returns>返回XmlReader结果集对象.</returns>
    public static XmlReader ExecuteXmlReaderTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
    {
        if( transaction == null ) throw new ArgumentNullException( "transaction" );
        if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        // 如果row有值,存储过程必须初始化.
        if( dataRow != null && dataRow.ItemArray.Length > 0)
        {
            // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
            SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
            
            // 分配参数值
            AssignParameterValues(commandParameters, dataRow);
            
            return SqlHelper.ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
        }
        else
        {
            return SqlHelper.ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
        }
    }
    #endregion
}

/// <summary>
/// SqlHelperParameterCache提供缓存存储过程参数,并能够在运行时从存储过程中探索参数.
/// </summary>
public sealed class SqlHelperParameterCache
{
    #region 私有方法,字段,构造函数
    // 私有构造函数,妨止类被实例化.
    private SqlHelperParameterCache() {}
    // 这个方法要注意
    private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());
    /// <summary>
    /// 探索运行时的存储过程,返回SqlParameter参数数组.
    /// 初始化参数值为 DBNull.Value.
    /// </summary>
    /// <param>一个有效的数据库连接</param>
    /// <param>存储过程名称</param>
    /// <param>是否包含返回值参数</param>
    /// <returns>返回SqlParameter参数数组</returns>
    private static SqlParameter[] DiscoverSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        SqlCommand cmd = new SqlCommand(spName, connection);
        cmd.CommandType = CommandType.StoredProcedure;
        connection.Open();
        // 检索cmd指定的存储过程的参数信息,并填充到cmd的Parameters参数集中.
        SqlCommandBuilder.DeriveParameters(cmd);
        connection.Close();
        // 如果不包含返回值参数,将参数集中的每一个参数删除.
        if (!includeReturnValueParameter) 
        {
            cmd.Parameters.RemoveAt(0);
        }
            
        // 创建参数数组
        SqlParameter[] discoveredParameters = new SqlParameter[cmd.Parameters.Count];
        // 将cmd的Parameters参数集复制到discoveredParameters数组.
        cmd.Parameters.CopyTo(discoveredParameters, 0);
        // 初始化参数值为 DBNull.Value.
        foreach (SqlParameter discoveredParameter in discoveredParameters)
        {
            discoveredParameter.Value = DBNull.Value;
        }
        return discoveredParameters;
    }
    
    /// <summary>
    /// SqlParameter参数数组的深层拷贝.
    /// </summary>
    /// <param>原始参数数组</param>
    /// <returns>返回一个同样的参数数组</returns>
    private static SqlParameter[] CloneParameters(SqlParameter[] originalParameters)
    {
        SqlParameter[] clonedParameters = new SqlParameter[originalParameters.Length];
        for (int i = 0, j = originalParameters.Length; i < j; i++)
        {
            clonedParameters = (SqlParameter)((ICloneable)originalParameters).Clone();
        }
        return clonedParameters;
    }
    #endregion 私有方法,字段,构造函数结束
        
    #region 缓存方法
    /// <summary>
    /// 追加参数数组到缓存.
    /// </summary>
    /// <param>一个有效的数据库连接字符串</param>
    /// <param>存储过程名或SQL语句</param>
    /// <param>要缓存的参数数组</param>
    public static void CacheParameterSet(string connectionString, string commandText, params SqlParameter[] commandParameters)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( commandText == null || commandText.Length == 0 ) throw new ArgumentNullException( "commandText" );
        string hashKey = connectionString + ":" + commandText;
        paramCache[hashKey] = commandParameters;
    }
    
    /// <summary>
    /// 从缓存中获取参数数组.
    /// </summary>
    /// <param>一个有效的数据库连接字符</param>
    /// <param>存储过程名或SQL语句</param>
    /// <returns>参数数组</returns>
    public static SqlParameter[] GetCachedParameterSet(string connectionString, string commandText)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( commandText == null || commandText.Length == 0 ) throw new ArgumentNullException( "commandText" );
        string hashKey = connectionString + ":" + commandText;
        SqlParameter[] cachedParameters = paramCache[hashKey] as SqlParameter[];
        if (cachedParameters == null)
        {            
            return null;
        }
        else
        {
            return CloneParameters(cachedParameters);
        }
    }
    #endregion 缓存方法结束
        
    #region 检索指定的存储过程的参数集
    /// <summary>
    /// 返回指定的存储过程的参数集
    /// </summary>
    /// <remarks>
    /// 这个方法将查询数据库,并将信息存储到缓存.
    /// </remarks>
    /// <param>一个有效的数据库连接字符</param>
    /// <param>存储过程名</param>
    /// <returns>返回SqlParameter参数数组</returns>
    public static SqlParameter[] GetSpParameterSet(string connectionString, string spName)
    {
        return GetSpParameterSet(connectionString, spName, false);
    }
    
    /// <summary>
    /// 返回指定的存储过程的参数集
    /// </summary>
    /// <remarks>
    /// 这个方法将查询数据库,并将信息存储到缓存.
    /// </remarks>
    /// <param>一个有效的数据库连接字符.</param>
    /// <param>存储过程名</param>
    /// <param>是否包含返回值参数</param>
    /// <returns>返回SqlParameter参数数组</returns>
    public static SqlParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
    {
        if( connectionString == null || connectionString.Length == 0 ) throw new ArgumentNullException( "connectionString" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        using(SqlConnection connection = new SqlConnection(connectionString))
        {
            return GetSpParameterSetInternal(connection, spName, includeReturnValueParameter);
        }
    }
    
    /// <summary>
    /// [内部]返回指定的存储过程的参数集(使用连接对象).
    /// </summary>
    /// <remarks>
    /// 这个方法将查询数据库,并将信息存储到缓存.
    /// </remarks>
    /// <param>一个有效的数据库连接字符</param>
    /// <param>存储过程名</param>
    /// <returns>返回SqlParameter参数数组</returns>
    internal static SqlParameter[] GetSpParameterSet(SqlConnection connection, string spName)
    {
        return GetSpParameterSet(connection, spName, false);
    }
    
    /// <summary>
    /// [内部]返回指定的存储过程的参数集(使用连接对象)
    /// </summary>
    /// <remarks>
    /// 这个方法将查询数据库,并将信息存储到缓存.
    /// </remarks>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名</param>
    /// <param>
    /// 是否包含返回值参数
    /// </param>
    /// <returns>返回SqlParameter参数数组</returns>
    internal static SqlParameter[] GetSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        using (SqlConnection clonedConnection = (SqlConnection)((ICloneable)connection).Clone())
        {
            return GetSpParameterSetInternal(clonedConnection, spName, includeReturnValueParameter);
        }
    }
    
    /// <summary>
    /// [私有]返回指定的存储过程的参数集(使用连接对象)
    /// </summary>
    /// <param>一个有效的数据库连接对象</param>
    /// <param>存储过程名</param>
    /// <param>是否包含返回值参数</param>
    /// <returns>返回SqlParameter参数数组</returns>
    private static SqlParameter[] GetSpParameterSetInternal(SqlConnection connection, string spName, bool includeReturnValueParameter)
    {
        if( connection == null ) throw new ArgumentNullException( "connection" );
        if( spName == null || spName.Length == 0 ) throw new ArgumentNullException( "spName" );
        string hashKey = connection.ConnectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter":"");
        SqlParameter[] cachedParameters;
        
        cachedParameters = paramCache[hashKey] as SqlParameter[];
        if (cachedParameters == null)
        {    
            SqlParameter[] spParameters = DiscoverSpParameterSet(connection, spName, includeReturnValueParameter);
            paramCache[hashKey] = spParameters;
            cachedParameters = spParameters;
        }
        
        return CloneParameters(cachedParameters);
    }
    
    #endregion 参数集检索结束
}

}