1.下载 或 在nuget安装 log4net







2. web.config (app.config)

<configuration>

  <configSections>

 <section name="log4net"

           type="log4net.Config.Log4NetConfigurationSectionHandler,

         log4net" />

 </configSections>

 <log4net>

    <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">

    <file type="log4net.Util.PatternString" value="C:\m1\eDASLog\%date{dd.MM.yyyy}.txt" />

    <appendToFile value="true" />

    <rollingStyle value="Date" />

    <datePattern value="yyyyMMdd" />

    <layout type="log4net.Layout.PatternLayout">

        <conversionPattern value="[[%date]] - %message %newline" />

    </layout>

</appender>

<root>

<level value="DEBUG"/>

<appender-ref ref="RollingLogFileAppender"/>

</root>

  </log4net>

</configuration>

为了每天一份log文件。做这个配置（文件节点类型为PatternString）：

<file type="log4net.Util.PatternString" value="C:\m1\eDASLog\%date{dd.MM.yyyy}.txt" />

3. 应用配置。在Application_Start(对于web 应用)中configure()：

log4net.Config.XmlConfigurator.Configure();

4.做一个简单的wrapper来使用：

 public static class EdasLogger

    {

        private static log4net.ILog Log { get; set; }

        static EdasLogger()

        {

            Log = log4net.LogManager.GetLogger(typeof(Logger));

        }

        public static void Error(object msg)

        {

            Log.Error(msg);

        }

        public static void Error(object msg, Exception ex)

        {

            Log.Error(msg, ex);

        }

        public static void Error(Exception ex)

        {

            Log.Error(ex.Message, ex);

        }

        public static void Info(object msg)

        {

            Log.Info(msg);

        }

    }