log4net:将log实时显示在textbox中（WinForm）

1、把log4net.dll添加到项目引用中

2、修改AssemblyInfo.cs，添加如下行：

[assembly: log4net.Config.XmlConfigurator(Watch  =   true )]

3、修改配置文件

<? xml version="1.0" encoding="utf-8"  ?>
< configuration >
     < configSections >
         < section  name ="log4net"  type ="System.Configuration.IgnoreSectionHandler"   />
     </ configSections >
     < log4net >
         < appender  name ="PatternFileAppender"  type ="SampleAppendersApp.Appender.PatternFileAppender, SampleAppendersApp" >
             < file  value ="%date{yyyy-MM-dd}\%property{session}\output.log"   />
             < layout  type ="log4net.Layout.PatternLayout"  value ="%date [%thread] %-5level %logger [%ndc] - %message%newline"   />
         </ appender >
         < root >
             < level  value ="ALL"   />
             < appender-ref  ref ="PatternFileAppender"   />
         </ root >
     </ log4net >
</ configuration >

4、Form1的代码如下：

using  System;
using  System.Collections.Generic;
using  System.ComponentModel;
using  System.Data;
using  System.Drawing;
using  System.Linq;
using  System.Text;
using  System.Windows.Forms;
using  System.Threading;
using  log4net.Core;

namespace  WinFormDemo
{
     public   partial   class  Form1 : Form
    {
         private   static   readonly  log4net.ILog log  =  log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
         private   bool  logWatching  =   true ;
         private  log4net.Appender.MemoryAppender logger;
         private  Thread logWatcher;


         public  Form1()
        {
            InitializeComponent();

             this .Closing  +=   new  CancelEventHandler(Form1_Closing);
            logger  =   new  log4net.Appender.MemoryAppender();

            log4net.Config.BasicConfigurator.Configure(logger);

            logWatcher  =   new  Thread( new  ThreadStart(LogWatcher));
            logWatcher.Start();

        }

         void  Form1_Closing( object  sender, CancelEventArgs e)
        {
            logWatching  =   false ;
            logWatcher.Join();

        }

         delegate   void  delOneStr( string  log);
         void  AppendLog( string  _log)
        {
             if  (txtLog.InvokeRequired)
            {
                delOneStr dd  =   new  delOneStr(AppendLog);
                txtLog.Invoke(dd,  new   object [] { _log});
            }
             else
            {                
                StringBuilder builder;
                 if  (txtLog.Lines.Length  >   99 )
                {
                    builder  =   new  StringBuilder(txtLog.Text);
                    builder.Remove( 0 , txtLog.Text.IndexOf( ' \r ' ,  3000 )  +   2 );
                    builder.Append(_log);
                    txtLog.Clear();
                    txtLog.AppendText(builder.ToString());
                }
                 else
                {
                    txtLog.AppendText(_log);
                }
            }

        }

         private   void  LogWatcher()
        {
             while  (logWatching)
            {
                LoggingEvent[] events  =  logger.GetEvents();
                 if  (events  !=   null   &&  events.Length  >   0 )
                {
                    logger.Clear();
                     foreach  (LoggingEvent ev  in  events)
                    {
                         string  line  =  ev.LoggerName  +   " :  "   +  ev.RenderedMessage  +   " \r\n " ;
                        AppendLog(line);
                    }
                }
                Thread.Sleep( 500 );
            }
        }

         private   void  timer1_Tick( object  sender, EventArgs e)
        {
            Random r  =   new  Random();

             int  x  =  r.Next( 1 ,  4 );

             switch  (x)
            {
                 case   1 :
                    log.Info( " 通知：通知通知通知 " );
                     break ;

                 case   2 :
                    log.Warn( " 警告：警告警告警告警告警告警告 " );
                     break ;
                 case   3 :
                    log.Error( " 错误：错误错误错误错误错误错误错误错误错误 " );
                     break ;
                 case   4 :
                    log.Fatal( " 严重：严重严重严重严重严重严重严重严重严重严重严重严重严重严重严重严重严重 " );
                     break ;
            }
        }

    }
}