LogHelper

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using log4net;

namespace xiaoy.Comm
{
  /// <summary>
    /// 日志类
    /// </summary>
    public class LogHelper
    {
        static log4net.ILog _log = null;
        static LogHelper()
        {
            log4net.Config.XmlConfigurator.ConfigureAndWatch(new FileInfo(AppDomain.CurrentDomain.BaseDirectory + "log4net.config"));
            _log =  log4net.LogManager.GetLogger("");
        }

        public static void Info(string msg)
        {
            _log.Info(msg);
        }

        public static void Debug(string msg)
        {
            _log.Debug(msg);
        }

        public static void Error(string msg)
        {
            _log.Error(msg);
        }

        public static void Error(string msg,Exception ex)
        {
            _log.Error(msg,ex);
        }

        public static void Error(Exception ex)
        {
            _log.Error(ex);
        }
    }
}

 log4net.config:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <section name="log4net" type="log4net.Config.log4NetConfigurationSectionHandler,log4net" />
    </configSections>
    <log4net>
        <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
        <!--定义输出到文件中 Debug和info 级别-->
        <appender name="InfoRollingFileAppender" type="log4net.Appender.RollingFileAppender">
            <!--定义文件存放位置-->
            <file value="log\\" />
            <appendToFile value="true" />
            <rollingStyle value="Date" />
            <!--日志文件路径和文件名称 -->
            <datePattern value="yyyyMM\\yyyyMMdd'_info.txt'" />
            <staticLogFileName value="false" />
            <param name="MaxSizeRollBackups" value="100" />
            <layout type="log4net.Layout.PatternLayout">
                <!--记录日志的格式内容-->
                <conversionPattern value="[%date] %-5level %message%newline" />
            </layout>
            <!--日志顺序 级别从低到高Debug，Info，Warn，Error，Fatal-->
            <filter type="log4net.Filter.LevelRangeFilter">
                <param name="LevelMin" value="INFO" />
                <param name="LevelMax" value="INFO" />
            </filter>
        </appender>
        <!--定义输出到文件中 Warn和error 级别-->
        <appender name="ErrorRollingFileAppender" type="log4net.Appender.RollingFileAppender">
            <!--定义文件存放位置-->
            <file value="log\\" />
            <appendToFile value="true" />
            <rollingStyle value="Date" />
            <!--日志文件路径和文件名称 -->
            <datePattern value="yyyyMM\\yyyyMMdd'_error.txt'" />
            <staticLogFileName value="false" />
            <param name="MaxSizeRollBackups" value="100" />
            <layout type="log4net.Layout.PatternLayout">
                <!--记录日志的格式内容-->
                <conversionPattern value="[%date] %-5level %message%newline" />
            </layout>
            <!--日志顺序 级别从低到高Debug，Info，Warn，Error，Fatal-->
            <filter type="log4net.Filter.LevelRangeFilter">
                <param name="LevelMin" value="Warn" />
                <param name="LevelMax" value="Error" />
            </filter>
        </appender>
        <!--定义输出到windows事件中-->
        <appender name="EventLogAppender" type="log4net.Appender.EventLogAppender">
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
            </layout>
        </appender>
        <!--定义输出到Console中-->
        <appender name="ColoredConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
            <mapping>
                <level value="ERROR" />
                <foreColor value="White" />
                <backColor value="Red, HighIntensity" />
            </mapping>
            <mapping>
                <level value="DEBUG" />
                <backColor value="Green" />
            </mapping>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
            </layout>
        </appender>
        <!--定义输出到数据库中，这里举例输出到sqlserver数据库中-->
        <appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">
            <bufferSize value="2" />
            <connectionType value="System.Data.SqlClient.SqlConnection, System.Data" />
            <connectionString value="server=(local);database=TestBase;integrated security=false;persist security info=True;UID=sa;PWD=" />
            <commandText value="INSERT INTO Log ([Date],[Thread],[Level],[Logger],[Message],[Exception]) VALUES (@log_date, @thread, @log_level, @logger, @message, @exception)" />
            <parameter>
                <parameterName value="@log_date" />
                <dbType value="DateTime" />
                <layout type="log4net.Layout.RawTimeStampLayout" />
            </parameter>
            <parameter>
                <parameterName value="@thread" />
                <dbType value="String" />
                <size value="255" />
                <layout type="log4net.Layout.PatternLayout">
                    <conversionPattern value="%thread" />
                </layout>
            </parameter>
            <parameter>
                <parameterName value="@log_level" />
                <dbType value="String" />
                <size value="50" />
                <layout type="log4net.Layout.PatternLayout">
                    <conversionPattern value="%level" />
                </layout>
            </parameter>
            <parameter>
                <parameterName value="@logger" />
                <dbType value="String" />
                <size value="255" />
                <layout type="log4net.Layout.PatternLayout">
                    <conversionPattern value="%logger" />
                </layout>
            </parameter>
            <parameter>
                <parameterName value="@message" />
                <dbType value="String" />
                <size value="4000" />
                <layout type="log4net.Layout.PatternLayout">
                    <conversionPattern value="%message" />
                </layout>
            </parameter>
            <parameter>
                <parameterName value="@exception" />
                <dbType value="String" />
                <size value="2000" />
                <layout type="log4net.Layout.ExceptionLayout" />
            </parameter>
        </appender>
        <root>
            <level value="ALL"/>
            <!--文件形式记录日志 ERROR-->
            <appender-ref ref="ErrorRollingFileAppender" />
            <appender-ref ref="InfoRollingFileAppender" />
            <!--Windows事件日志-->
            <!--<appender-ref ref="EventLogAppender" />-->
            <!-- 如果不启用相应的日志记录，可以通过这种方式注释掉
              <appender-ref ref="AdoNetAppender" />
              -->
            <!--console日志
            <appender-ref ref="ColoredConsoleAppender" />-->

        </root>
    </log4net>
</configuration>