在ASP.NET中使用SOAP Extensions捕獲WebService異常

Application_Error不能捕獲的異常

      [WebMethod]        public string HelloWorld()        {            throw new Exception("this exption can't be handled by Application_Error Method");            return "Hello World";        }

定義Application_Error將不能捕獲這個異常.

原因需要瞭解一下SOAP請求的在ASP.NET的生命週期.

 

Process Message程序呼叫WebMethod時如果產生SoapException,SoapHeaderException 被序列化後,返回在SOAP <Fault>結點.

使用SOAP extension擴充處理Process Message過程產生的異常
我們可以SOAP Extension處理

Code
public class SoapExceptionHandler : System.Web.Services.Protocols.SoapExtension
    {
        public override void ProcessMessage(System.Web.Services.Protocols.SoapMessage message)
        {
            if (message.Stage == SoapMessageStage.AfterSerialize)
            {
                if (message.Exception != null)
                {
                    LogUtil.Log.Error(message.Exception.InnerException);
                }
            }
        }

        public override object GetInitializer(Type serviceType)
        {
            return null;
        }

        public override object GetInitializer(
            LogicalMethodInfo methodInfo,
            SoapExtensionAttribute attribute)
        {
            return null;
        }

        public override void Initialize(object initializer) 
        {
        }
    }

在Web.config system.web結點中配置

Code
        <webServices>
            <soapExtensionTypes>
                <add type="Elplan.App.SoapExceptionHandler, Elplan.App" priority="1" group="High" />
            </soapExtensionTypes>
        </webServices>

調試:

如果使用VS直接運行調試asmx,是不可以的.(因為...它不是一個完整的SOAP請求.)可使用WebServiceStudio.
相關地址:http://www.codeplex.com/WebserviceStudio 

參考文章:

Using SOAP Extensions in ASP.NET
Handling and Throwing Exceptions in XML Web Services
How to create a global exception handler for a Web Service