c#

1.连接字符串

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using MySql.Data.MySqlClient;
using System.Data.OleDb;

    private DataSet sqlMethod(string sql)
    {
        MySqlConnection conn = new MySqlConnection("Database=dream;Data Source=localhost;User Id=root;Password=123456");
        MySqlDataAdapter da = new MySqlDataAdapter(sql, conn);
        DataSet ds = new DataSet();
        conn.Open();
        da.Fill(ds);
        conn.Close();
        return ds;
    }
    private int sqlMethodNoDataset(string sql)
    {
        MySqlConnection conn = new MySqlConnection("Provider=MySqlOLEDB;; Database=dream;Data Source=localhost;User Id=root;Password=123456");
        conn.Open();
        MySqlCommand cmd = new MySqlCommand();
        cmd.Connection = conn;
        cmd.CommandText = sql;
        int result = cmd.ExecuteNonQuery();
        conn.Close();
        return result;
    }

2.cookie的创建与删除
3.判断是否存在cookie

       if (Request.Cookies["user_id"] == null)
        {
            //Response.Write("<Script>alert(\"请先登录\")</script>");
            //Response.Redirect("index_login.aspx");
        }
        else
        {
            HttpCookie hc = Request.Cookies["user_id"];
            user_id = hc.Value;
        }