log4net是一個優秀的開源日志項目，現將本人使用寫成一個demo，如下

0:準備
去http://logging.apache.org/，可下載log4net，最新為1.2版本，
建立一個asp.net web 項目，并將log4net.dll添加到引用

1：建立數據表
CREATE TABLE [dbo].[Log] (
[Id] [int] IDENTITY (1, 1) NOT NULL,
[Date] [datetime] NOT NULL,
[Thread] [varchar] (255) NOT NULL,
[Level] [varchar] (50) NOT NULL,
[Logger] [varchar] (255) NOT NULL,
[Message] [varchar] (4000) NOT NULL,
[Exception] [varchar] (2000) NULL
)


2：編寫配置文件
<configuration>
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
</configSections>

<system.web>
<!--
......
-->
</system.web>

<log4net>

<root>
<level value="ALL" />
<appender-ref ref="ADONetAppender" />
</root>

<!--
<logger name="testApp.Logging">
<level value="ALL"/>
<appender-ref ref="ADONetAppender" />

</logger>
-->

<appender name="ADONetAppender" type="log4net.Appender.ADONetAppender">
<bufferSize value="10" />
<connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
<connectionString value="server=localhost;database=demo;user id=sa;password=123456" />
<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>

</log4net>

</configuration>

特別說明<bufferSize value="10" />，這是log信息記錄的緩沖大小，(比如只有log信息記錄達到10，
才會將log信息記錄寫入數據庫)

3：在Global.asax.cs中
protected void Application_Start(Object sender, EventArgs e)
{
//讀取配置信息
log4net.Config.DOMConfigurator.Configure();
}
4：一個使用log的demo類
using System;

namespace Log
{
/// <summary>
/// MyLog 的摘要說明。
/// </summary>
public class MyLog
{
private static readonly log4net.ILog log = log4net.LogManager.GetLogger(typeof(MyLog));
public static void LogInfo()
{
log.Info("log日志");
}

public static void LogError()
{
log.Info("log錯誤");
}
}
}
5：資源：
my blog:http://tomch.donews.net/tomch/posts/22457.aspx
主站 logging.apache.org/
學習使用log4net的文章 www.ondotnet.com/pub/a/dotnet/2003/06/16/log