原創地址：http://www.cnblogs.com/jfzhu/p/4060666.html
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前面的文章《WCF服務的異常消息》中介紹過，如果WCF Service發生異常時，Service會將異常序列化為SOAP Fault並發送給客戶端。
默認情況下，出於安全原因，WCF Service中未處理的異常的詳細信息不會包括在發送給客戶的SOAP Fault里，你只能看到一個通用的SOAP Fault（“The server was unable to process the request due to an internal error.”）。在調試程序的時候，如果想在SOAP Fault中包含異常的詳細信息，可以修改服務器的配置文件。
<behaviors> <serviceBehaviors> <behavior name="includeExceptionDetails"> <serviceDebug includeExceptionDetailInFaults="true" /> </behavior> </serviceBehaviors> </behaviors>
SOAP Fault是XML格式，與平台無關。通常一個SOAP Fault包含以下節點
(1) faultcode
(2) faultstring
(3) detail
Detail節點可以用來包括自定義XML信息。
WCF Service在發生異常時應拋出FaultException或FaultException<T>，而不應該拋出.NET Exception，出於以下兩個原因：
（1）未處理的.NET Exception會使服務器與客戶端之間的channel變為Fault狀態，繼而導致client proxy無法使用。
（2）.NET Exception只能被.NET平台理解，而FaultException與平台無關。如果想跨平台使用，需要使用FaultException。
下面還是以中《WCF服務的異常消息》的例子來分別演示如何拋出與處理FaultException與強類型的FaultException<T>。
（一）使用FaultException
IDemoService.cs：
using System.ServiceModel; namespace WCFDemo { [ServiceContract(Name = "IDemoService")] public interface IDemoService { [OperationContract] int Divide(int numerator, int denominator); } }
DemoService.cs：
using System; using System.ServiceModel; using System.ServiceModel.Activation; namespace WCFDemo { [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class DemoService : IDemoService { public int Divide(int numerator, int denominator) { if (denominator == 0) { throw new FaultException("Denominator cannot be ZERO!", new FaultCode("DivideByZeroFault")); } return numerator / denominator; } } }
client:
private void buttonCalculate_Click(object sender, EventArgs e) { try { textBoxResult.Text = demoServiceClient.Divide(Convert.ToInt32(textBoxNumerator.Text), Convert.ToInt32(textBoxDenominator.Text)).ToString(); } catch (FaultException fault) { MessageBox.Show(fault.Code + " - " + fault.Message); } }
SOAP Fault XML
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"> <s:Body> <s:Fault> <faultcode>s:DivideByZeroFault</faultcode> <faultstring xml:lang="en-US">Denominator cannot be ZERO!</faultstring> </s:Fault> </s:Body> </s:Envelope>
（二）使用強類型FaultException<T>
（1）創建一個自定義SOAP Fault類
DivideByZeroFault.cs：
using System.Runtime.Serialization; namespace WCFDemo { [DataContract] public class DivideByZeroFault { [DataMember] public string Error { get; set; } [DataMember] public string Detail { get; set; } } }
（2） 在Service方法上使用FaultContractAttribute來指示哪個操作可以使用哪個Fault
IDemoService.cs：
using System.ServiceModel; namespace WCFDemo { [ServiceContract(Name = "IDemoService")] public interface IDemoService { [FaultContract(typeof(DivideByZeroFault))] [OperationContract] int Divide(int numerator, int denominator); } }
DemoService.cs：
using System; using System.ServiceModel; using System.ServiceModel.Activation; namespace WCFDemo { [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class DemoService : IDemoService { public int Divide(int numerator, int denominator) { try { return numerator / denominator; } catch (DivideByZeroException ex) { DivideByZeroFault fault = new DivideByZeroFault(); fault.Error = ex.Message; fault.Detail = "Denominator cannot be ZERO!"; throw new FaultException<DivideByZeroFault>(fault); } } } }
client:
private void buttonCalculate_Click(object sender, EventArgs e) { try { textBoxResult.Text = demoServiceClient.Divide(Convert.ToInt32(textBoxNumerator.Text), Convert.ToInt32(textBoxDenominator.Text)).ToString(); } catch (FaultException<DemoServiceReference.DivideByZeroFault> fault) { MessageBox.Show(fault.Detail.Error + " - " + fault.Detail.Detail); } }
返回的SOAP Fault XML:
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"> <s:Body> <s:Fault> <faultcode>s:Client</faultcode> <faultstring xml:lang="en-US">The creator of this fault did not specify a Reason.</faultstring> <detail> <DivideByZeroFault xmlns="http://schemas.datacontract.org/2004/07/WCFDemo" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"> <Detail>Denominator cannot be ZERO!</Detail> <Error>Attempted to divide by zero.</Error> </DivideByZeroFault> </detail> </s:Fault> </s:Body> </s:Envelope>
