log4net 在作为网络服务运行时以静默方式失败

您是否考虑过为 FileAppender 设置错误处理程序？

您可以使用以下代码获取配置文件中设置的 FileAppender：

var fileAppenders = LogManager.GetAllRepositories().SelectMany(repository => repository.GetAppenders()).OfType<FileAppender>();
foreach (var fileAppender in fileAppenders) {
    fileAppender.ErrorHandler = new MyErrorHandler();
}

其中 MyErrorHandler 类有点像这样：

class MyErrorHandler : IErrorHandler {
    public void Error(string messages) {
        // giver error message and abort
    }
    public void Error(string messages, Exception exception) {
        // giver error message and abort
    }
    public void Error(string messages, Exception exception, ErrorCode errorCode) {
        // giver error message and abort
    }
}

我不确定"给予者错误消息和中止"像往常一样简单，您在服务中没有 GUI 访问权限

FileAppender 成员如下所示：http://logging.apache.org/log4net/release/sdk/html/AllMembers_T_log4net_Appender_FileAppender.htmIErrorHandler 成员在这里：http://logging.apache.org/log4net/release/sdk/html/AllMembers_T_log4net_Core_IErrorHandler.htm

您可能还想在 repository.ConfigurationChanged 注册活动

有了詹斯的一些提示，我能够做到这一点。

app.config - 添加了此行

 <errorHandler type="Log4NetTesting.util.CustomLogErrorHandler" />

自定义日志错误处理程序

  public class LogException : Exception
    {
        private readonly ErrorCode errorCode;
        /// <summary>Gets the service name which related to this exception.</summary>
        public ErrorCode ErrorCode
        {
            get { return errorCode; }
        }
        public LogException()
        {
        }
        public LogException(string message)
            : base(message)
        {
        }
        public LogException(string message, Exception inner)
            : base(message, inner)
        {
        }
        public LogException(string message, Exception inner, ErrorCode errorCode)
            : base(message, inner)
        {
            this.errorCode = errorCode;
        }
    }
    public class CustomLogErrorHandler : IErrorHandler
    {
        public string message { get;private set; }
        public Exception Exception { get; private set; }
        public ErrorCode ErrorCode { get; private set; }
        #region IErrorHandler Members
        public void Error(string message)
        {
            this.message = message;
        }
        public void Error(string message, Exception e)
        {
            this.message = message;
            this.Exception = e;
        }
        public void Error(string message, Exception e, ErrorCode errorCode)
        {
            this.message = message;
            this.Exception = e;
            this.ErrorCode = errorCode;
        }
        #endregion
    }

测试它

 try
            {                
                string logFile = @"D:'TaskDev'Log4NetTesting'Log4NetTesting'bin'Debug'Test'Log4netTesting.Log";
                log4net.GlobalContext.Properties["LogFileName"] = logFile;
                log4net.Config.XmlConfigurator.Configure();
                log4net.NDC.Push("Test Application");
                ILog log = log4net.LogManager.GetLogger(typeof(Program));
                var fileAppenders = LogManager.GetAllRepositories().SelectMany(repository => repository.GetAppenders()).OfType<FileAppender>();
                var customLogErrorHandler = new CustomLogErrorHandler();  // custom error IErrorHandler. 
                // loop though fileappenders adding the error handler
                foreach (var fileAppender in fileAppenders)
                {
                    fileAppender.ErrorHandler = customLogErrorHandler;
                }
                log.Info("hello Log file");
                if (customLogErrorHandler.message != null)   // if there is an error throw exception
                {
                    throw new LogException(customLogErrorHandler.message, customLogErrorHandler.Exception, customLogErrorHandler.ErrorCode);
                }
            }
            catch (LogException lex) {
                // catch log exception
                Console.WriteLine(lex.ErrorCode);
                Console.WriteLine(lex.Message);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

虽然我知道默默失败对某些人来说可能是件好事。 对于我的应用程序，如果我没有日志文件，并且 Log4Net 无法告诉我它有问题，我们的用户无法知道存在问题。

您可以执行以下操作来验证配置是否有效：

if(!LogManager.GetRepository().Configured)
{
    XmlConfigurator.Configure();
}
if (!LogManager.GetRepository().Configured)
{
    var logMsg = new StringBuilder();
    logMsg.AppendLine("Failed to initialize log4net");
    foreach(var msg in LogManager.GetRepository().ConfigurationMessages)
    {
        logMsg.AppendLine(msg.ToString());
    }
    // ....do something with the message, raise
    // an evt to UI, log to OS Event logger, etc....
}