Prism6下的MEF：添加Logger

上篇已经简单的构建了一个Prism的程序，现在我们需要添加一个Logger，Prism本身自带一个功能简单的TextLogger，但是我们希望能用.Net常用的Log4net。所以我们需要重载掉Bootstrapper中的CreateLogger方法。

新建一个PrismSample.Infrastructure.Logger项目

从nuget中引用log4net的，添加配置文件logging.confing:

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

<configuration>

    <configSections>

        <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>

    </configSections>

    <log4net>

        <logger name="logerror">

        <level value="ERROR" />

        <appender-ref ref="ErrorAppender" />

        </logger>

        <logger name="loginfo">

        <level value="INFO" />

        <appender-ref ref="InfoAppender" />

        </logger>

        <logger name="logwarn">

        <level value="WARN" />

        <appender-ref ref="WarnAppender" />

        </logger>

        <logger name="logdebug">

        <level value="DEBUG" />

        <appender-ref ref="DebugAppender" />

        </logger>

        <appender name="ErrorAppender" type="log4net.Appender.RollingFileAppender">

        <param name="File" value="App_Log\Error\ErrorLog.log" />

        <param name="AppendToFile" value="true" />

        <param name="MaxSizeRollBackups" value="100" />

        <param name="MaximumFileSize" value="1MB" />

        <param name="RollingStyle" value="Size" />

        <param name="StaticLogFileName" value="true" />

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

            <param name="ConversionPattern" value="%-5p %d [%c] %m%n" />

        </layout>

        </appender>

        <appender name="InfoAppender" type="log4net.Appender.RollingFileAppender">

        <param name="File" value="App_Log\Info\InfoLog.log" />

        <param name="AppendToFile" value="true" />

        <param name="MaxSizeRollBackups" value="100" />

        <param name="MaximumFileSize" value="1MB" />

        <param name="RollingStyle" value="Size" />

        <param name="StaticLogFileName" value="true" />

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

            <param name="ConversionPattern" value="%-5p %d [%c] %m%n" />

        </layout>

        </appender>

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

        <param name="File" value="App_Log\Debug\DebugLog.log" />

        <param name="AppendToFile" value="true" />

        <param name="MaxSizeRollBackups" value="100" />

        <param name="MaximumFileSize" value="1MB" />

        <param name="RollingStyle" value="Size" />

        <param name="StaticLogFileName" value="true" />

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

            <param name="ConversionPattern" value="%-5p %d [%c] %m%n" />

        </layout>

        </appender>

        <appender name="WarnAppender" type="log4net.Appender.RollingFileAppender">

        <param name="File" value="App_Log\Warn\WarnLog.log" />

        <param name="AppendToFile" value="true" />

        <param name="MaxSizeRollBackups" value="100" />

        <param name="MaximumFileSize" value="1MB" />

        <param name="RollingStyle" value="Size" />

        <param name="StaticLogFileName" value="true" />

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

            <param name="ConversionPattern" value="%-5p %d [%c] %m%n" />

        </layout>

        </appender>

    </log4net>

</configuration>

新建Logger类：

using log4net;

using log4net.Config;

using Prism.Logging;

using System;

using System.IO;

namespace PrismSample.Infrastructure.Logger

{

    public class Logger : ILoggerFacade

    {

        private ILog _debugLogger;

        private ILog _errorLogger;

        private ILog _infoLogger;

        private ILog _warnLogger;

        public Logger()

        {

            var logCfg = new FileInfo(AppDomain.CurrentDomain.BaseDirectory + "logging.config");

            XmlConfigurator.ConfigureAndWatch(logCfg);

            _debugLogger = LogManager.GetLogger("logdebug");

            _errorLogger = LogManager.GetLogger("logerror");

            _infoLogger = LogManager.GetLogger("loginfo");

            _warnLogger = LogManager.GetLogger("logwarn");

        }

        public void Log(string message, Category category, Priority priority)

        {

            switch(category)

            {

                case Category.Debug:

                    _debugLogger.Debug(message ?? "");

                    break;

                case Category.Exception:

                    _errorLogger.Error(message ?? "");

                    break;

                case Category.Info:

                    _infoLogger.Info(message ?? "");

                    break;

                case Category.Warn:

                    _warnLogger.Warn(message ?? "");

                    break;

            }

        }

    }

}

PrismSample添加Logger项目的引用，并重载掉Bootstrapper中的CreateLogger方法：

protected override ILoggerFacade CreateLogger()

{

    return new Logger();

}

Logger之所以不使用导入的方式是因为Logger的初始化在容器的初始化之前，我们预期Logger在程序已启动就配置完成，这样我们能记录容器初始化的过程。

测试Logger

修改ShellViewModel的构造函数如下：

[ImportingConstructor]

public ShellViewModel([Import("ShellView", typeof(IView))]IView view, [Import]ILoggerFacade logger)

{

    this.View = view;

    this._text = "Hello World";

    this.View.DataContext = this;

    logger.Log("ShellViewModel Created", Category.Info, Priority.None);

}

运行后打开Logger文件：

现在整个项目的组织结构如下：

小结

本文演示了log4net在Prism中的简单应用。

源码下载

参考信息

[Prism框架实用分享]如何在Prism应用程序中使用日志