TryGetValueFromConfig：读取配置信息时防止出

using System;
using System.Configuration;
using System.Diagnostics;
using System.Runtime.CompilerServices;

public sealed class ConfigHelper
{
    private static readonly ConfigHelper _instance = null;

    #region Constructors
    static ConfigHelper()
    {
        _instance = new ConfigHelper();
    }

    private ConfigHelper() { }
    #endregion

    public static ConfigHelper Instance { get { return _instance; } }

    /// <summary>
    /// 转换Appsetting节点信息为指定类型
    /// </summary>
    /// <typeparam name="T">类型</typeparam>
    /// <param name="parseFunc">需要转换的类型</param>
    /// <param name="defaultTValueFunc">类型默认值</param>
    /// <param name="key">AppSetting节点name</param>
    /// <returns>节点类型</returns>
    public T TryGetValueFromConfig<T>(Func<string, T> parseFunc, Func<T> defaultTValueFunc, [CallerMemberName]string key = "")
    {
        try
        {
            var node = ConfigurationManager.AppSettings[key];
            return !string.IsNullOrWhiteSpace(node) ? parseFunc(node) : defaultTValueFunc();
        }
        catch (Exception ex)
        {
            Trace.Write(ex.Message);
            return default(T);
        }
    }

}