Exception catch ,Using Log4Net save exception message to a file.

Default.aspx.cs

1    protected void Page_Load(object sender, EventArgs e)
2    {
3        log4net.ILog logger = log4net.LogManager.GetLogger("File");
4        logger.Info("測試!此文字將寫入Log4Net.log");
5
6        throw new Exception("Err");
7        //故意throw new Exception，將會觸發Global.asax中Application_Error方法
8        //將Exception.Message()寫入Log4Net.log檔案中
9    }

Global.asax

 1    void Application_Error(object sender, EventArgs e) 
 2    {
 3        Exception ex = HttpContext.Current.Server.GetLastError();
 4        string ErrPage = Request.Url.ToString();
 5        StringBuilder errorMessage = new StringBuilder();
 6        string brFlag = "===============================<br />\n";
 7        
 8        if ( ex != null )
 9        {
10            while ( ex != null )
11            {
12                errorMessage.Append("<strong>Date</strong><br />" + ex.Data + "<br /><br />");
13                errorMessage.Append("<strong>Message</strong><br />" + ex.Message + "<br /><br />");
14                errorMessage.Append("<strong>Source</strong><br />" + ex.Source + "<br /><br />");
15                errorMessage.Append("<strong>Target site</strong><br />" + ex.TargetSite.ToString() + "<br /><br />");
16                errorMessage.Append("<strong>Stack trace</strong><br />" + ex.StackTrace + "<br /><br />");
17                errorMessage.Append("<strong>ToString()</strong><br />" + ex.ToString() + "<br /><br />");
18                errorMessage.Append(brFlag);
19                ex = ex.InnerException;
20            }
21        }
22
23        log4net.ILog logger = log4net.LogManager.GetLogger("File");
24        logger.Info(errorMessage);
25    }

web.config

<?xml version="1.0"?>
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
    <configSections>
        <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
    </configSections>
    <appSettings/>
    <connectionStrings/>
  <system.web>
        <compilation debug="true"/>
        <authentication mode="Forms"/>
    
    </system.web>
    <log4net>
        <appender name="LogFileAppender" type="log4net.Appender.FileAppender">
            <param name="File" value="Log4Net.log"/>
            <layout type="log4net.Layout.PatternLayout">
                <param name="ConversionPattern" value="%d [%t] %-5p %c %m%n"/>
            </layout>
        </appender>
        <logger name="File">
            <level value="Debug"/>
            <appender-ref ref="LogFileAppender"/>
        </logger>
    </log4net>
</configuration>

<param name="File" value="Log4Net.log"/>
                                           ~~~~~~~~~ Log filename

When exception raise will create a log file (Log4Net.log).