在.Net Compact Framework中使用 log4net_综合

转自http://breathingtech.com/2009/using-apache-log4net-in-net-compact-framework-projects/

When developing all kind of projects a good strategy for logging can save you a lot of time and frustration. Personally I am very found of using Apache log4net and this post will describe the most important features in log4net and how to implement and use this in a .Net Compact Framework project.

log4net can be configured with different appenders that logs to different sources (file, output window, smtp, server ++). You can also configure what kind of log levels will be written to the different appenders (info, debug, warn, error and fatal).

Most of the time I use two different appenders: I use the DebugAppender to log to my output window in Visual Studio, I like to set this appender to log all levels. I also like to use a LogFileAppender to log to a file on the device, I usually set this appender to only log error and fatal.

You can read documentation and download Apache log4net at http://logging.apache.org/log4net/index.html

I will show you a simple example on how to use log4net in a .Net Compact Framework project:

First you create a new Smart Device project and chose Device application. I am using Visual Studio 2008, Windows Mobile 6 professional SDK as target platform and .Net Compact Framework 3.5

The first thing you need to do after creating the project is to add the log4net.dll as a reference (log4net.dll can be downloaded from the link above).

Then you need to add a xml configuration file for log4net in your project, I added a file called Config.xml in my project and set the property to content/copy always. In this configuration file you add and setup all the different appenders and what level they will log on. You can also defined a layout pattern for the log text.

Below you can see my very simple Config.xml file containing a LogFileAppender and a DebugAppender and they are both set to log all levels.

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

<log4net>

<appender name="LogFileAppender" type="log4net.Appender.FileAppender" >

<file value="log-file.txt" />

<appendToFile value="true" />

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

<conversionPattern value="%date [%-5level] - %message%newline" />

</layout>

</appender>

<appender name="DebugAppender" type="log4net.Appender.DebugAppender">

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

<conversionPattern value="%date [%-5level] - %message%newline" />

</layout>

</appender>

<!-- Setup the root category, add the appenders

and set the default level -->

<root>

<level value="ALL" />

<appender-ref ref="DebugAppender" />

<appender-ref ref="LogFileAppender" />

</root>

</log4net>

</configuration>

In your Main method (by default found in Program.cs) you need to configure log4net based on the Config.xml file

 
    //Load Config.xml to setup log4net 
   
    string path = System.IO.Path.GetDirectoryName( 
   
        System.Reflection.Assembly.GetExecutingAssembly() 
   
       .GetModules()[0].FullyQualifiedName) 
   
       + "//Config.xml"; 
   
    if (System.IO.File.Exists(path)) 
   
    {
      
          XmlConfigurator.Configure(new System.IO.FileInfo(path)); 
   
    }

log4net are now ready to be used in all classes throughout your project. For each class you want to use log4net create a static logger object in top of your class. Remember that the typeof () must be set to the class you create this logger in.

 
      // Create a logger for use in this class 
     
      private static readonly log4net.ILog Log = log4net.LogManager.GetLogger(typeof (Program)); 
     
      //I often use the logger to log exceptions but I also use it for information and debug. 
     
      //Information logging 
     
      Log.Info("Application startup"); 
     
      //Debug logging 
     
      Log.Debug("Debug statement"); 
     
      //Warning logging 
     
      Log.Warn("Could not find all images"); 
     
      //Exception logging 
     
      catch(Exception ex) 
     
      {
        
           Log.Error("Custom exception message", ex); 
     
      }

The log file on the device can be found under program files/yourProjectName/log-file.txt. This text file on the device is a very good place to for example log your global exception handling.