化零为整WCF(4) - 异常处理(Exception、FaultException、FaultException、IErrorHandler)

介绍
WCF(Windows Communication Foundation) - 异常处理：一般Exception的处理，FaultException和FaultException<T>的抛出和处理，使用IErrorHandler处理异常。


示例
1、服务
IHello.cs

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;

using  System.ServiceModel;

namespace  WCF.ServiceLib.Exception
{
     /**/ ///   <summary>
     ///  IHello接口
     ///   </summary>
    [ServiceContract]
     public   interface  IHello
     {
         /**/ ///   <summary>
         ///  抛出Exception异常
         ///   </summary>
        [OperationContract]
         void  HelloException();

         /**/ ///   <summary>
         ///  抛出FaultException异常
         ///   </summary>
        [OperationContract]
         void  HelloFaultException();

         /**/ ///   <summary>
         ///  抛出FaultException <T> 异常
         ///   </summary>
        [OperationContract]
        [FaultContract( typeof (FaultMessage))]
         void  HelloFaultExceptionGeneric();

         /**/ ///   <summary>
         ///  IErrorHandler处理异常
         ///   </summary>
        [OperationContract]
         void  HelloIErrorHandler();
    }
}

FaultMessage.cs

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;

using  System.ServiceModel;
using  System.Runtime.Serialization;

namespace  WCF.ServiceLib.Exception
{
     /**/ ///   <summary>
     ///  错误信息实体类（用于错误契约FaultContract）
     ///   </summary>
    [DataContract]
     public   class  FaultMessage
     {
         /**/ ///   <summary>
         ///  错误信息
         ///   </summary>
        [DataMember]
         public   string  Message  {  get ;  set ; }

         /**/ ///   <summary>
         ///  错误代码
         ///   </summary>
        [DataMember]
         public   int  ErrorCode  {  get ;  set ; }
    }
}

FaultErrorHandler.cs

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;

using  System.ServiceModel.Dispatcher;
using  System.Configuration;
using  System.ServiceModel;
using  System.ServiceModel.Channels;

namespace  WCF.ServiceLib.Exception
{
     /**/ ///   <summary>
     ///  自定义错误处理器（继承自System.ServiceModel.Dispatcher.IErrorHandler）
     ///   </summary>
     public   class  FaultErrorHandler : IErrorHandler
     {
         /**/ ///   <summary>
         ///  在异常返回给客户端之后被调用
         ///   </summary>
         ///   <param name="error"> 异常 </param>
         ///   <returns></returns>
         public   bool  HandleError(System.Exception error)
         {
            System.IO.StreamWriter sw  =   new  System.IO.StreamWriter( @" C:/WCF_Log.txt " ,  true );
            sw.Write( " IErrorHandler - HandleError测试。错误类型：{0}；错误信息：{1} " , error.GetType().ToString(), error.Message);
            sw.WriteLine();
            sw.Flush();
            sw.Close();

             //  true - 已处理
             return   true ;
        }

         /**/ ///   <summary>
         ///  在异常发生后，异常信息返回前被调用
         ///   </summary>
         ///   <param name="error"> 异常 </param>
         ///   <param name="version"> SOAP版本 </param>
         ///   <param name="fault"> 返回给客户端的错误信息 </param>
         public   void  ProvideFault(System.Exception error, System.ServiceModel.Channels.MessageVersion version,  ref  System.ServiceModel.Channels.Message fault)
         {
             if  (error  is  System.IO.IOException)
             {
                FaultException ex  =   new  FaultException( " IErrorHandler - ProvideFault测试 " );

                MessageFault mf  =  ex.CreateMessageFault();

                fault  =  Message.CreateMessage(version, mf, ex.Action);

                 //  InvalidOperationException error = new InvalidOperationException("An invalid operation has occurred.");
                 //  MessageFault mfault = MessageFault.CreateFault(new FaultCode("Server", new FaultCode(String.Format("Server.{0}", error.GetType().Name))), new FaultReason(error.Message), error);
                 //  FaultException fe = FaultException.CreateFault(mfault, typeof(InvalidOperationException));
            }
        }
    }
}

Hello.cs

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;

using  System.ServiceModel;
using  System.ServiceModel.Description;
using  System.ServiceModel.Dispatcher;

namespace  WCF.ServiceLib.Exception
{
     /**/ ///   <summary>
     ///  Hello类
     ///   </summary>
     public   class  Hello : IHello, IDisposable, IServiceBehavior 
     {
         /**/ ///   <summary>
         ///  抛出Exception异常
         ///   </summary>
         public   void  HelloException()
         {
             throw   new  System.Exception( " 抛出Exception异常 " );
        }

         /**/ ///   <summary>
         ///  抛出FaultException异常
         ///   </summary>
         public   void  HelloFaultException()
         {
             throw   new  FaultException( " 抛出FaultException异常 " ,  new  FaultCode( " 服务 " ));
        }

         /**/ ///   <summary>
         ///  抛出FaultException <T> 异常
         ///   </summary>
         public   void  HelloFaultExceptionGeneric()
         {
             throw   new  FaultException < FaultMessage > ( new  FaultMessage  { Message  =   " 抛出FaultException<T>异常 " , ErrorCode  =   - 1  } ,  " 为了测试FaultException<T>用的 " );
        }

         /**/ ///   <summary>
         ///  IErrorHandler处理异常
         ///   </summary>
         public   void  HelloIErrorHandler()
         {
             throw   new  System.IO.IOException( " 抛出异常，用IErrorHandler处理 " );
        }

         /**/ ///   <summary>
         ///  实现IDisposable接口的Dispose()方法
         ///   </summary>
         public   void  Dispose()
         {

        }

         /**/ ///   <summary>
         ///  为契约增加自定义绑定参数
         ///   </summary>
         ///   <param name="serviceDescription"> 服务描述 </param>
         ///   <param name="serviceHostBase"> 服务宿主 </param>
         ///   <param name="endpoints"> 服务端点 </param>
         ///   <param name="bindingParameters"> 需要增加的自定义绑定参数 </param>
         public   void  AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, System.Collections.ObjectModel.Collection < ServiceEndpoint >  endpoints, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
         {

        }

         /**/ ///   <summary>
         ///  runtime时修改属性值或增加自定义扩展对象
         ///   </summary>
         ///   <param name="serviceDescription"> 服务描述 </param>
         ///   <param name="serviceHostBase"> 服务宿主 </param>
         public   void  ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
         {
            IErrorHandler handler  =   new  FaultErrorHandler();

             foreach  (ChannelDispatcher dispatcher  in  serviceHostBase.ChannelDispatchers)
             {
                 //  增加错误处理器
                dispatcher.ErrorHandlers.Add(handler);
            }
        }

         /**/ ///   <summary>
         ///  检查服务描述和服务宿主，以确认服务可以成功运行
         ///   </summary>
         ///   <param name="serviceDescription"> 服务描述 </param>
         ///   <param name="serviceHostBase"> 服务宿主 </param>
         public   void  Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
         {

        }
    }
}

2、宿主
Hello.svc

<% @ ServiceHost Language = " C# "  Debug = " true "  Service = " WCF.ServiceLib.Exception.Hello "   %>

Web.config

<? xml version="1.0" ?>
< configuration >
   < system.serviceModel >
     < behaviors >
       < serviceBehaviors >
         < behavior  name ="ExceptionBehavior" >
           <!-- httpGetEnabled - 使用get方式提供服务 -->
           < serviceMetadata  httpGetEnabled ="true"   />
           < serviceDebug  includeExceptionDetailInFaults ="true" />
         </ behavior >
       </ serviceBehaviors >
     </ behaviors >
     < services >
       <!-- name - 提供服务的类名 -->
       <!-- behaviorConfiguration - 指定相关的行为配置 -->
       < service  name ="WCF.ServiceLib.Exception.Hello"  behaviorConfiguration ="ExceptionBehavior" >
         <!-- address - 服务地址 -->
         <!-- binding - 通信方式 -->
         <!-- contract - 服务契约 -->
         < endpoint  address =""  binding ="wsHttpBinding"  contract ="WCF.ServiceLib.Exception.IHello"   />
       </ service >
     </ services >
   </ system.serviceModel >
</ configuration >

3、客户端
Hello.aspx

<% @ Page Language = " C# "  MasterPageFile = " ~/Site.master "  AutoEventWireup = " true "  CodeFile = " Hello.aspx.cs "
    Inherits = " Exception_Hello "  Title = " 异常处理(Exception、FaultException、FaultException&lt;T&gt;、IErrorHandler) "   %>

< asp:Content  ID ="Content1"  ContentPlaceHolderID ="head"  runat ="Server" >
</ asp:Content >
< asp:Content  ID ="Content2"  ContentPlaceHolderID ="ContentPlaceHolder1"  runat ="Server" >
     < div >
         < asp:Label  ID ="lblMsg"  runat ="server"   />
     </ div >
     < br  />
     < div >
         < asp:Button  ID ="btnHelloException"  runat ="server"  Text ="HelloException"  OnClick ="btnHelloException_Click"   />
     </ div >
     < div >
         < asp:Button  ID ="btnHelloFaultException"  runat ="server"  Text ="HelloFaultException"
            OnClick ="btnHelloFaultException_Click"   />
     </ div >
     < div >
         < asp:Button  ID ="btnHelloFaultExceptionGeneric"  runat ="server"  Text ="HelloFaultExceptionGeneric"
            OnClick ="btnHelloFaultExceptionGeneric_Click"   />
     </ div >
     < div >
         < asp:Button  ID ="btnHelloIErrorHandler"  runat ="server"  Text ="HelloIErrorHandler"  OnClick ="btnHelloIErrorHandler_Click"   />
     </ div >
</ asp:Content >

Hello.aspx.cs

using  System;
using  System.Collections;
using  System.Configuration;
using  System.Data;
using  System.Linq;
using  System.Web;
using  System.Web.Security;
using  System.Web.UI;
using  System.Web.UI.HtmlControls;
using  System.Web.UI.WebControls;
using  System.Web.UI.WebControls.WebParts;
using  System.Xml.Linq;

using  System.ServiceModel;

public   partial   class  Exception_Hello : System.Web.UI.Page
{
     protected   void  Page_Load( object  sender, EventArgs e)
     {

    }

     protected   void  btnHelloException_Click( object  sender, EventArgs e)
     {
        ExceptionService.HelloClient proxy  =   new  ExceptionService.HelloClient();
         try
         {
            proxy.HelloException();
        }
         catch  (Exception ex)
         {
            lblMsg.Text  =  ex.Message;
        }
         finally
         {
             try
             {
                proxy.Close();
            }
             catch  (Exception ex)
             {
                lblMsg.Text  +=   " <br /> "   +  ex.Message;
            }
        }
    }

     protected   void  btnHelloFaultException_Click( object  sender, EventArgs e)
     {
        ExceptionService.HelloClient proxy  =   new  ExceptionService.HelloClient();
         try
         {
            proxy.HelloFaultException();
        }
         catch  (FaultException ex)
         {
            lblMsg.Text  =   string .Format( " 错误编码：{0}；错误原因：{1} " ,
                ex.Code.Name,
                ex.Reason.ToString());
        }
         finally
         {
            proxy.Close();
        }
    }

     protected   void  btnHelloFaultExceptionGeneric_Click( object  sender, EventArgs e)
     {
        ExceptionService.HelloClient proxy  =   new  ExceptionService.HelloClient();
         try
         {
            proxy.HelloFaultExceptionGeneric();
        }
         catch  (System.ServiceModel.FaultException < ExceptionService.FaultMessage >  ex)
         {
            lblMsg.Text  =   string .Format( " 错误代码：{0}；错误信息：{1}；错误原因：{2} " ,
                ex.Detail.ErrorCode.ToString(),
                ex.Detail.Message,
                ex.Reason.ToString());
        }
         finally
         {
            proxy.Close();
        }
    }

     protected   void  btnHelloIErrorHandler_Click( object  sender, EventArgs e)
     {
        ExceptionService.HelloClient proxy  =   new  ExceptionService.HelloClient();
         try
         {
            proxy.HelloIErrorHandler();
        }
         catch  (Exception ex)
         {
            System.ServiceModel.FaultException faultException  =  ex  as  System.ServiceModel.FaultException;

             if  (faultException  !=   null )
             {
                lblMsg.Text  =   string .Format( " 错误信息：{0} " , faultException.Message);
            }
             else
             {
                lblMsg.Text  =  ex.ToString();
            }
        }
         finally
         {
            proxy.Close();
        }
    }
}

Web.config

<? xml version="1.0" ?>
< configuration >
   < system.serviceModel >
     < client >
       <!-- address - 服务地址 -->
       <!-- binding - 通信方式 -->
       <!-- contract - 服务契约 -->
       < endpoint  address ="http://localhost:3502/ServiceHost/Exception/Hello.svc"  binding ="wsHttpBinding"  contract ="ExceptionService.IHello"   />
     </ client >
   </ system.serviceModel >
</ configuration >

运行结果：
单击"btnHelloException"后显示
抛出Exception异常
The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in the Faulted state.

单击"btnHelloFaultException"后显示
错误编码：服务；错误原因：抛出FaultException异常

单击"btnHelloFaultExceptionGeneric"后显示
错误代码：-1；错误信息：抛出FaultException异常；错误原因：为了测试FaultException用的

单击"btnHelloIErrorHandler"后显示
错误信息：IErrorHandler - ProvideFault测试


OK
[源码下载]