Prism 4 ILoggerFacade for Log4Net?

I am converting from Prism 2.1 to Prism 4, and I need to write an ILoggerFacade class for Log4Net. My old code from Prism 2.1 no longer works. Does anyone have sample code for an ILoggerFacade class they'd be wil开发者_如何学Goling to share? Thanks for your help.

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I figured it out. Very similar to Prism 2. First, create a custom logger class that implements ILoggerFacade. Here's my class:

using log4net;
using Microsoft.Practices.Prism.Logging;

namespace FsNoteMaster3
{
    class Log4NetLogger : ILoggerFacade
    {
        #region Fields

        // Member variables
        private readonly ILog m_Logger = LogManager.GetLogger(typeof(Log4NetLogger)); 

        #endregion

        #region ILoggerFacade Members

        /// <summary>
        /// Writes a log message.
        /// </summary>
        /// <param name="message">The message to write.</param>
        /// <param name="category">The message category.</param>
        /// <param name="priority">Not used by Log4Net; pass Priority.None.</param>
        public void Log(string message, Category category, Priority priority)
        {
            switch (category)
            {
                case Category.Debug:
                    m_Logger.Debug(message);
                    break;
                case Category.Warn:
                    m_Logger.Warn(message);
                    break;
                case Category.Exception:
                    m_Logger.Error(message);
                    break;
                case Category.Info:
                    m_Logger.Info(message);
                    break;
            }
        }

        #endregion
    }
}

Then, in the Prism 4 Bootstrapper class, add an override to the CreateLogger() method that returns a new instance of the custom logger class:

protected override Microsoft.Practices.Prism.Logging.ILoggerFacade CreateLogger()
{
    return new Log4NetLogger();
}

Note that in the custom logger class, ILog is a Log4Net interface, and LogManager is a Log4Net object.

Writing to the custom logger from your own code (Prism takes care of its own log entries)is a little different than in Prism 2.1. You can resolve the logger directly from the IoC container, or you can use the ServiceLocator. The ServiceLocator has the advantage of being container-agnostic, which means the underlying container doesn't really matter. Here is an example of resolving a logger using the ServiceLocator:

var logger = (Log4NetLogger)ServiceLocator.Current.GetInstance(typeof(ILoggerFacade));
logger.Log("App.OnStartup() completed", Category.Info ,Priority.None);

The ServiceLocator requires that the host project have a reference to Microsoft.Practices.ServiceLocation.dll and a matching using statement.