ASP.NET AJAX Web服务和内部错误500

我可以使用以下url直接将webservice调用到浏览器,它将返回我想要的所有内容:

http://localhost:64438/MySearchAutoComplete.asmx/GetCompletionList

当我将其添加到autocompleteexetender的default.aspx页面时,如下所示:

<cc1:AutoCompleteExtender ID="AutoCompleteExtender1" 
                  TargetControlID="TextBox1" 
                  runat="server" 
                  ServiceMethod="GetCompletionList" 
                  ServicePath="http://localhost:64438/MySearchAutoComplete.asmx" 
                  CompletionSetCount="12"
                  MinimumPrefixLength="1" />

页面加载时,我有一个文本框,但每次在文本框中添加击键时都会出现错误500。我在firefox firebug中看到了错误。

http://localhost:62702/   --->This is the webpage that load fine 

alt text http://clip2net.com/clip/m12122/1269451120-clip-2kb.png -->这是错误

有什么想法吗?我注意到我需要附加进程来调试webservice,我可能也会对它做一些错误的事情?

编辑(事件查看器)

如果我转到我机器的事件查看器。我可以看到:

Exception information: 
    Exception type: InvalidOperationException 
    Exception message: Request format is unrecognized for URL unexpectedly ending in '/GetCompletionList'. 


    Thread information: 
    Thread ID: 8 
    Thread account name: MTL\daok 
    Is impersonating: False 
    Stack trace:    at     System.Web.Services.Protocols.WebServiceHandlerFactory.CoreGetHandler(Type type, HttpContext context, HttpRequest request, HttpResponse response)
   at System.Web.Services.Protocols.WebServiceHandlerFactory.GetHandler(HttpContext context, String verb, String url, String filePath)
   at System.Web.HttpApplication.MapHttpHandler(HttpContext context, String requestType, VirtualPath path, String pathTranslated, Boolean useAppConfig)
   at System.Web.HttpApplication.MapHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

我还必须首先启动webservice项目,而不是停止它并启动webproject才能同时拥有这两个项目。webservice仍然有效(我可以直接启动它 http://localhost:64438/MySearchAutoComplete.asmx?op=GetCompletionList )但在网页上我仍然有错误500。

编辑2(web.config)

添加到webservice项目web.config:

  <webServices>
    <protocols>
      <add   name="HttpGet"/>
      <add   name="HttpPost"/>
    </protocols>
  </webServices>

没有解决问题。

编辑3(直接呼叫)

在page_load()中调用来自webservice的相同方法非常有效:

     string[] stuffs;
     stuffs = proxy.GetCompletionList("1", 10);
     MyList.DataSource = stuffs;
     MyList.DataBind();

但它不能与autocompleteextender一起工作…