SoapRpcMethodAttribute.OneWay引发的错误

为方法添加了OneyWay属性，测试页可以继续使用，但是客户端调用就出错了（删除oneway属性后正常使用）
报告的错误为：
************** 异常文本 **************
System.InvalidOperationException: 客户端发现响应内容类型为“”，但应该是“text/xml”。

   at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)
   at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
   at Favorite.FavoriteService.FavoriteService.DelSingleFile(String path) in c:\documents and settings\camitsc\my documents\visual studio projects\favorite\web references\favoriteservice\reference.cs:line 141
   at Favorite.Form2.button2_Click(Object sender, EventArgs e) in c:\documents and settings\camitsc\my documents\visual studio projects\favorite\form2.cs:line 87
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.Button.WndProc(Message& m)
   at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

苦恼中....