爲什麼在調用ExceptionPolicy.HandleException時收到System.InvalidOperationException？

Question

我正在開發一個測試程序，幫助我弄清楚如何使用Microsoft.Practices.EnterpriseLibrary.ExceptionHandling框架。該程序定義了幾種自定義異常類型，並將自定義異常處理程序與每種類型關聯在運行時，程序會提示異常拋出的類型的用戶，拋出異常，並使用ExceptionHandling框架呼籲異常類型相應的異常處理程序：

using System; 
using System.Collections.Specialized; 
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration; 
using Microsoft.Practices.EnterpriseLibrary.ExceptionHandling; 
using Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Configuration; 

namespace ConsoleApplication1 
{ 
    public class AException : Exception { public AException(string message) : base(message) { } } 
    public class BException : Exception { public BException(string message) : base(message) { } } 
    public class BBException : BException { public BBException(string message) : base(message) { } } 

    public class WrapperException : Exception 
    { 
     public WrapperException(Exception innerException) 
      : base("Wrapped exception: [" + innerException.Message + "]", innerException) { } 
    } 

    public class MyExceptionHandler<T> : IExceptionHandler 
    { 
     protected NameValueCollection Ignore { get; set; } 
     public MyExceptionHandler(NameValueCollection ignore) 
     { 
      Ignore = ignore; 
     } 

     #region IExceptionHandler Members 

     public virtual Exception HandleException(Exception exception, Guid handlingInstanceId) 
     { 
      if (exception is T) 
      { 
       Console.WriteLine("Exception Handled:"); 
       Console.WriteLine(" Expected Type : [{0}]", typeof(T).ToString()); 
       Console.WriteLine(" Actual Type : [{0}]", exception.GetType().ToString()); 
       Console.WriteLine(" Message  : [{0}]", exception.Message); 
       Console.WriteLine(); 
      } 
      else 
      { 
       Console.WriteLine("Unexpected Exception Type: [{0}]", exception.GetType().ToString()); 
      } 
      return exception; 
     } 

     #endregion 
    } 

    [ConfigurationElementType(typeof(CustomHandlerData))] 
    public class AExceptionHandler : MyExceptionHandler<AException> 
    { 
     public AExceptionHandler(NameValueCollection ignore) : base(ignore) { } 
    } 

    [ConfigurationElementType(typeof(CustomHandlerData))] 
    public class BExceptionHandler : MyExceptionHandler<BException> 
    { 
     public BExceptionHandler(NameValueCollection ignore) : base(ignore) { } 
    } 

    [ConfigurationElementType(typeof(CustomHandlerData))] 
    public class ExceptionHandler : MyExceptionHandler<Exception> 
    { 
     public ExceptionHandler(NameValueCollection ignore) : base(ignore) { } 

     public override Exception HandleException(Exception exception, Guid handlingInstanceId) 
     { 
      var wrapper = new WrapperException(exception); 
      return base.HandleException(wrapper, handlingInstanceId); 
     } 
    } 


    class Program 
    { 
     static void ThrowSomething() 
     { 
      Console.Write("Enter the exception type: "); 
      var x = Console.ReadLine(); 
      if (x.Equals("a")) 
      { 
       throw new AException(x); 
      } 
      else if (x.Equals("b")) 
      { 
       throw new BException(x); 
      } 
      else if (x.Equals("bb")) 
      { 
       throw new BBException(x); 
      } 
      else 
      { 
       throw new Exception(x); 
      } 
     } 

     static void Main(string[] args) 
     { 
      ExceptionManager xm = EnterpriseLibraryContainer.Current.GetInstance<ExceptionManager>(); 
      while (true) 
      { 
       //xm.Process(ThrowSomething, "Policy"); 
       try 
       { 
        ThrowSomething(); 
       } 
       catch(Exception ex) 
       { 
        Exception exToThrow = null; 
        if (ExceptionPolicy.HandleException(ex, "policy", out exToThrow)) 
        { 
         if (exToThrow == null) 
         { 
          throw; 
         } 
         else 
         { 
          throw exToThrow; 
         } 
        } 
       } 
       Console.WriteLine(); 
      } 
     } 
    } 
} 

在這第一次迭代程序，我使用ExceptionManager.Process（）方法來調用我的ThrowSomething（）方法。使用這種方法，一切都很好。然後我修改了Main來使用ExceptionPolicy.HandleException（）。當我這樣做，我開始此異常：

未處理的異常： Microsoft.Practices.ServiceLocation.ActivationException：激活嘗試獲取類型 ExceptionPolicyImpl，關鍵的「政策」的情況下 出錯--- > Microsoft.Practices.Unity.ResolutionFailedException：分辨率的 依賴失敗，類型= 「Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl」， 名 = 「政策」。發生異常時：解析時。異常是：InvalidOperationException - 類型ExceptionPolicyImpl有多個長度爲2的構造函數 。無法消除歧義。

我App.config文件包含以下內容：

<?xml version="1.0" encoding="utf-8" ?> 
<configuration> 
    <configSections> 
     <section name="exceptionHandling" type="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Configuration.ExceptionHandlingSettings, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" /> 
    </configSections> 
    <exceptionHandling> 
     <exceptionPolicies> 
      <add name="Policy"> 
       <exceptionTypes> 
        <add name="AException" type="ConsoleApplication1.AException, ConsoleApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" 
         postHandlingAction="None"> 
         <exceptionHandlers> 
          <add type="ConsoleApplication1.AExceptionHandler, ConsoleApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" 
           name="AExceptionHandler" /> 
         </exceptionHandlers> 
        </add> 
        <add name="BException" type="ConsoleApplication1.BException, ConsoleApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" 
         postHandlingAction="None"> 
         <exceptionHandlers> 
          <add type="ConsoleApplication1.BExceptionHandler, ConsoleApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" 
           name="BExceptionHandler" /> 
         </exceptionHandlers> 
        </add> 
        <add name="All Other Exceptions" type="System.Exception, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" 
         postHandlingAction="NotifyRethrow"> 
         <exceptionHandlers> 
          <add type="ConsoleApplication1.ExceptionHandler, ConsoleApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" 
           name="ExceptionHandler" /> 
         </exceptionHandlers> 
        </add> 
       </exceptionTypes> 
      </add> 
     </exceptionPolicies> 
    </exceptionHandling> 
</configuration> 

誰能告訴我爲什麼我收到此異常以及如何解決這個問題呢？

Answer 1

嗯，我覺得很蠢。問題在於拼寫「政策」的小寫字母「p」而不是大寫的「P」。改變線

if (ExceptionPolicy.HandleException(ex, "policy", out exToThrow)) 

到

if (ExceptionPolicy.HandleException(ex, "Policy", out exToThrow)) 

固定的問題。