Question

我正在开发一个测试程序，帮助我弄清楚如何使用Microsoft.Practices.EnterpriseLibrary.ExceptionHandling框架。该程序定义了几种自定义异常类型，并将自定义异常处理程序与每种类型相关在运行时，程序会提示用户输入异常类型，抛出异常，并使用ExceptionHandling框架为异常类型调用适当的异常处理程序：

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();
            }
        }
    }
}

在这个程序的第一次迭代中，我使用ExceptionManager.Process（）方法来调用我的ThrowSomething（）方法。使用这种方法，一切都很好。然后我修改了Main以使用ExceptionPolicy.HandleException（）代替。当我这样做时，我开始得到这个例外：

未处理的例外情况： Microsoft.Practices.ServiceLocation.ActivationException：激活尝试获取类型实例时发生错误 ExceptionPolicyImpl，关键“策略”---＆gt; Microsoft.Practices.Unity.ResolutionFailedException：解析依赖失败，type = “Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl” 名称 =“政策”。在解决时发生异常：例外情况是：InvalidOperationException - ExceptionPolicyImpl类型有多个长度为2的构造函数。无法消除歧义。

我的App.config文件包含以下内容：

<?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>

任何人都可以告诉我为什么我会收到此异常以及如何解决问题？

Answer 1

嗯，我觉得很蠢。问题是拼写为“policy”的小写“p”而不是大写的“P”。改变行

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

到

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

修复了问题。

为什么我在调用ExceptionPolicy.HandleException时遇到System.InvalidOperationException？

1 个答案: