Question

我在为Enterprise Library 6.0日志记录组件设置logwriter时遇到异常。在第一次发生日志记录时，它会成功。但对于连续调用，它会引发异常：The LogWriter is already set.我试过检查Logger.Writer是否为空。但是这在第一个实例中失败了，除了我应该使用Logger.SetLogWriter设置编写器。

这是我的代码：

if (Logger.Writer == null)  // fails on first call
{
    IConfigurationSource configurationSource = ConfigurationSourceFactory.Create();
    LogWriterFactory logWriterFactory = new LogWriterFactory(configurationSource);
    Logger.SetLogWriter(logWriterFactory.Create()); // fails on subsequent calls.
}

Answer 1

试试这个：

IConfigurationSource configurationSource = ConfigurationSourceFactory.Create();
LogWriterFactory logWriterFactory = new LogWriterFactory(configurationSource);
Logger.SetLogWriter(logWriterFactory.Create(), false);

Answer 2

使用6.0版本时我也遇到了同样的问题。我通过创建自己的静态记录器类并在构造函数中初始化SetLogWriter（）来解决这个问题。以下是代码：

using System;
using ms = Microsoft.Practices.EnterpriseLibrary.Logging;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;

namespace LoggingService
{
    public static class Logger
    {
        static Logger()
        {
            try
            {
                IConfigurationSource configurationSource = ConfigurationSourceFactory.Create();
                ms.LogWriterFactory logWriterFactory = new ms.LogWriterFactory(configurationSource);
                ms.Logger.SetLogWriter(new ms.LogWriterFactory().Create());
            }
            catch (Exception)
            {
            }
        }
        /// <summary>
        /// Writes exception details to the log using Enterprise Library
        /// </summary>
        /// <param name="ex"></param>
        public static void Log(Exception ex)
        {
// can be changed as per your requirement for the event/priority and the category
            ms.Logger.Write(ex, "ErrorsWarnings", 1, 1, System.Diagnostics.TraceEventType.Error);
        }
        /// <summary>
        /// Writes Information message to the log using Enterprise Library
        /// </summary>
        /// <param name="infoMsg"></param>
        public static void Log(string infoMsg)
        {
            ms.Logger.Write(infoMsg);
        }
    }
}

简单地使用

Logger.Log(ex);
//or
Logger.Log("Your message");

Answer 3

答案是使用静态变量以便只获取一个logwriter实例

这样做：

public class BaseController : Controller
{
    private static ExceptionManager _exceptionManager;
    private static LogWriter _logWriter;

    public ExceptionManager ExceptionManager
    {
        get
        {
            IUnityContainer container = new UnityContainer();
            try
            {
                if (_exceptionManager == null)
                {
                    IConfigurationSource configurationSource = ConfigurationSourceFactory.Create();
                    ExceptionPolicyFactory exceptionFactory = new ExceptionPolicyFactory(configurationSource);

                    if (configurationSource.GetSection(LoggingSettings.SectionName) != null)
                    {
                        LogWriterFactory logWriterFactory = new LogWriterFactory(configurationSource);
                        Logger.SetLogWriter(logWriterFactory.Create());

                    }

                    container.RegisterInstance<ExceptionManager>(exceptionFactory.CreateManager());
                    _exceptionManager = container.Resolve<ExceptionManager>();
                    return _exceptionManager;
                }
                else
                {
                    return _exceptionManager;
                }
            }
            finally
            {
                ((IDisposable)container).Dispose();
            }

        }
        set
        {
            _exceptionManager = value;
        }
    }

    /// <summary>
    /// Used to log entries in the log file
    /// </summary>
    public LogWriter LogWriter
    {
        get
        {
            IUnityContainer container = new UnityContainer();
            try
            {
                if (_logWriter == null)
                {
                    IConfigurationSource configurationSource = ConfigurationSourceFactory.Create();
                    LogWriterFactory logWriterFactory = new LogWriterFactory(configurationSource);
                    Logger.SetLogWriter(logWriterFactory.Create());
                    // Singleton
                    container.RegisterInstance<LogWriter>(logWriterFactory.Create());
                    _logWriter = container.Resolve<LogWriter>();
                    return _logWriter;
                }
                else
                    return _logWriter;
            }
            finally
            {
                ((IDisposable)container).Dispose();
            }
        }
        set
        {
            _logWriter = value;
        }
    }


    protected override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        Thread.CurrentThread.CurrentUICulture = new CultureInfo("es");
        Thread.CurrentThread.CurrentCulture = new CultureInfo("es");

        if (Session.Count == 0)
        {
            filterContext.Result = new RedirectToRouteResult(new RouteValueDictionary { { "controller", "Account" }, { "action", "Login" } });
        }

    }

    protected override void OnException(ExceptionContext filterContext)
    {
        this.ExceptionManager.HandleException(filterContext.Exception, "AllExceptionsPolicy");

        //Show basic Error view
        filterContext.ExceptionHandled = true;

        //Clear any data in the model as it wont be needed
        ViewData.Model = null;

        //Show basic Error view
        View("Error").ExecuteResult(this.ControllerContext);

    }

}

Answer 4

您是否检查过web.config（如果是asp.net）或app.config（如果是控制台或Windows应用程序）中没有任何LogWriter设置。

另请参阅此线程中如何使用LogWriter（Microsoft.Practices.EnterpriseLibrary.Logging.dll）

How to set and use more than one formatter for a trace listener in EntLib log app block

Answer 5

在早期版本中，我们使用了

var logWriter = EnterpriseLibraryContainer.Current.GetInstance<LogWriter>();

EnterpriseLibraryContainer返回相同的实例。

但是使用EL 6.0，LibraryContainer将被删除。但是，Logger似乎只能保留一个一次性初始化的编写器。

我在静态变量的帮助下解决了这个问题，以检查编写器是否已初始化。或者，它可以通过单例或静态实体来完成。

Answer 6

Logger.SetLogWriter(logWriterFactory.Create(), false);

默认情况下throwIfSet标志设置为true，如果已经设置了日志编写器，则会抛出异常。

entlib 6记录器实例化中的错误

6 个答案: