<?xml version="1.0" encoding="utf-8"?>
<configuration>
 <configSections>
  <!--添加自定义节点：log4net type：解析类名，程序集名(log4net.dll)-->
  <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
 </configSections>

 <log4net>
  <!--定义输出到文件中-->
  <appender name="Log4Net_INFO" type="log4net.Appender.RollingFileAppender">
   <!--定义文件存放位置-->
   <file value="C:/log4net/"/>
   <!--是否追加到文件,默认为true，通常无需设置-->
   <appendToFile value="true"/>
   <RollingStyle value="Date"/>
   <!--日期的格式，每天换一个文件记录，如不设置则永远只记录一天的日志，需设置-->
   <DatePattern value="INFO_yyyyMMdd".log"" />
   <!--日志文件名是否为静态-->
   <StaticLogFileName value="false"/>
   <!--多线程时采用最小锁定-->
   <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
   <!--布局（向用户显示最后经过格式化的输出信息）-->
   <layout type="log4net.Layout.PatternLayout">
    <!--
      %m(message):输出的日志消息，如ILog.Debug(…)输出的一条消息 
      %n(new line):换行 
      %d(datetime):输出当前语句运行的时刻 
      %r(run time):输出程序从运行到执行到当前语句时消耗的毫秒数 
      %t(thread id):当前语句所在的线程ID 
      %p(priority): 日志的当前优先级别，即DEBUG、INFO、WARN…等 
      %c(class):当前日志对象的名称，例如：
      %L：输出语句所在的行号 
      %F：输出语句所在的文件名 
      %-数字：表示该项的最小长度，如果不够，则用空格填充
     -->
    <Header value="[Header]
"/>
    <Footer value="[Footer]
"/>
    <!--正文-->
    <ConversionPattern value="记录时间：%date 线程ID:[%thread] 日志级别：%-5level 出错类：%logger property:[%property{NDC}] - 错误描述：%message%newline" />
   </layout>
  </appender>

  <appender name="Log4Net_ERROR" type="log4net.Appender.RollingFileAppender">
   <file value="C:/log4net/"/>
   <appendToFile value="true"/>
   <RollingStyle value="Date"/>
   <DatePattern value="ERROR_yyyyMMdd".log"" />
   <StaticLogFileName value="false"/>
   <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
   <layout type="log4net.Layout.PatternLayout">
    <Header value="[Header]
"/>
    <Footer value="[Footer]
"/>
    <!--正文-->
    <ConversionPattern value="记录时间：%date 线程ID:[%thread] 日志级别：%-5level 出错类：%logger property:[%property{NDC}] - 错误描述：%message%newline" />
   </layout>
  </appender>

  <root>
   <level value="DEBUG"/>
   <appender-ref ref="Log4Net_ERROR" />

   <level value="INFO"/>
   <appender-ref ref="Log4Net_INFO" />
  </root>

 </log4net>

</configuration>

using log4net;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;

//指定log4net使用的config文件来读取配置信息
[assembly: log4net.Config.XmlConfigurator(ConfigFile = @"LogConfig\Log4Net.config", Watch = true)]
namespace Project.Log4.Net.LogConfig
{
  /// <summary>
  /// 日志帮助类
  /// </summary>
  public class LogHelper
  {
    private static readonly ConcurrentDictionary<Type, ILog> _loggers = new ConcurrentDictionary<Type, ILog>();

    /// <summary>
    /// 获取记录器
    /// </summary>
    /// <param name="source"></param>
    /// <returns></returns>
    private static ILog GetLogger(Type source)
    {
      if (_loggers.ContainsKey(source))
      {
        return _loggers[source];
      }
      else
      {
        ILog logger = LogManager.GetLogger(source);
        _loggers.TryAdd(source, logger);
        return logger;
      }
    }

    /* Log a message object */

    /// <summary>
    /// 调试信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Debug(object source, string message)
    {
      Debug(source.GetType(), message);
    }

    /// <summary>
    /// 调试信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="ps"></param>
    public static void Debug(object source, string message, params object[] ps)
    {
      Debug(source.GetType(), string.Format(message, ps));
    }

    /// <summary>
    /// 调试信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Debug(Type source, string message)
    {
      ILog logger = GetLogger(source);
      if (logger.IsDebugEnabled)
        logger.Debug(message);
    }

    /// <summary>
    /// 关键信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Info(object source, object message)
    {
      Info(source.GetType(), message);
    }

    /// <summary>
    /// 关键信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Info(Type source, object message)
    {
      ILog logger = GetLogger(source);
      if (logger.IsInfoEnabled)
        logger.Info(message);
    }

    /// <summary>
    /// 警告信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Warn(object source, object message)
    {
      Warn(source.GetType(), message);
    }

    /// <summary>
    /// 警告信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Warn(Type source, object message)
    {
      ILog logger = GetLogger(source);
      if (logger.IsWarnEnabled)
        logger.Warn(message);
    }

    /// <summary>
    /// 错误信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Error(object source, object message)
    {
      Error(source.GetType(), message);
    }

    /// <summary>
    /// 错误信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Error(Type source, object message)
    {
      ILog logger = GetLogger(source);
      if (logger.IsErrorEnabled)
        logger.Error(message);
    }

    /// <summary>
    /// 失败信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Fatal(object source, object message)
    {
      Fatal(source.GetType(), message);
    }

    /// <summary>
    /// 失败信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    public static void Fatal(Type source, object message)
    {
      ILog logger = GetLogger(source);
      if (logger.IsFatalEnabled)
        logger.Fatal(message);
    }

    /* Log a message object and exception */

    /// <summary>
    /// 调试信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Debug(object source, object message, Exception exception)
    {
      Debug(source.GetType(), message, exception);
    }

    /// <summary>
    /// 调试信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Debug(Type source, object message, Exception exception)
    {
      GetLogger(source).Debug(message, exception);
    }

    /// <summary>
    /// 关键信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Info(object source, object message, Exception exception)
    {
      Info(source.GetType(), message, exception);
    }

    /// <summary>
    /// 关键信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Info(Type source, object message, Exception exception)
    {
      GetLogger(source).Info(message, exception);
    }

    /// <summary>
    /// 警告信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Warn(object source, object message, Exception exception)
    {
      Warn(source.GetType(), message, exception);
    }

    /// <summary>
    /// 警告信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Warn(Type source, object message, Exception exception)
    {
      GetLogger(source).Warn(message, exception);
    }

    /// <summary>
    /// 错误信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Error(object source, object message, Exception exception)
    {
      Error(source.GetType(), message, exception);
    }

    /// <summary>
    /// 错误信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Error(Type source, object message, Exception exception)
    {
      GetLogger(source).Error(message, exception);
    }

    /// <summary>
    /// 失败信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Fatal(object source, object message, Exception exception)
    {
      Fatal(source.GetType(), message, exception);
    }

    /// <summary>
    /// 失败信息
    /// </summary>
    /// <param name="source"></param>
    /// <param name="message"></param>
    /// <param name="exception"></param>
    public static void Fatal(Type source, object message, Exception exception)
    {
      GetLogger(source).Fatal(message, exception);
    }
  }

}

LogHelper.Debug(this, "Debug");
LogHelper.Error(this, "Error");
LogHelper.Fatal(this, "Fatal");
LogHelper.Info(this, "Info");
LogHelper.Warn(this, "Warn");