I have a wcf service that uses callbacks with DualHttpBindings. The service pushes back a datatable of search results the client (for a long running search) as it finds them.
This worked fine in .Net 3.5. Since I updated to .Net 4.0, it bombs out with a System.Runtime.FatalException that actually kills the IIS worker process. I have no idea how to even go about starting to fix this. Any recommendations appreciated.
The info from the resulting event logs is pasted below:
An unhandled exception occurred and
the process was terminated.Application ID: /LM/W3SVC/2/ROOT/CP
Process ID: 5284
> Exception:
System.Runtime.FatalException> Message: Object reference not set to
an instance of an object.StackTrace: at
System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc&
rpc) at
System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc&
rpc) at
System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean
isOperationContextSet) at
System.ServiceModel.Dispatcher.ChannelHandler.DispatchAndReleasePump(RequestContext
request, Boolean cleanThread,
OperationContext
currentOperationContext) at
System.ServiceModel.Dispatcher.ChannelHandler.HandleRequest(RequestContext
request, OperationContext
currentOperationContext) at
System.ServiceModel.Dispatcher.ChannelHandler.AsyncMessagePump(IAsyncResult
result) at
System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult
result) at
System.Runtime.AsyncResult.Complete(Boolean
completedSynchronously) at
System.Runtime.InputQueue1.AsyncQueueReader.Set(Item
1.Dispatch()
item) at
System.Runtime.InputQueue
at
System.ServiceModel.Channels.ReliableDuplexSessionChannel.ProcessDuplexMessage(WsrmMessageInfo
info) at
System.ServiceModel.Channels.ReliableDuplexSessionChannel.HandleReceiveComplete(IAsyncResult
result) at
System.ServiceModel.Channels.ReliableDuplexSessionChannel.OnReceiveCompletedStatic(IAsyncResult
result) at
System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult
result) at
System.Runtime.AsyncResult.Complete(Boolean
completedSynchronously) at
System.ServiceModel.Channels.ReliableChannelBinder1.InputAsyncResult
1.OnInputComplete(IAsyncResult
result) at
System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult
result) at
System.Runtime.AsyncResult.Complete(Boolean
completedSynchronously) at
System.Runtime.InputQueue1.AsyncQueueReader.Set(Item
1.Dispatch()
item) at
System.Runtime.InputQueue
at
System.Runtime.IOThreadScheduler.ScheduledOverlapped.IOCallback(UInt32
errorCode, UInt32 numBytes,
NativeOverlapped* nativeOverlapped)
at
System.Runtime.Fx.IOCompletionThunk.UnhandledExceptionFrame(UInt32
error, UInt32 bytesRead,
NativeOverlapped* nativeOverlapped)
at
System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32
errorCode, UInt32 numBytes,
NativeOverlapped* pOVERLAP)> InnerException:
> System.NullReferenceExceptionMessage: Object reference not set to
an instance of an object.StackTrace: at
System.Web.HttpApplication.ThreadContext.Enter(Boolean
setImpersonationContext) at
System.Web.HttpApplication.OnThreadEnterPrivate(Boolean
setImpersonationContext) at
System.Web.AspNetSynchronizationContext.CallCallbackPossiblyUnderLock(SendOrPostCallback
callback, Object state) at
System.Web.AspNetSynchronizationContext.CallCallback(SendOrPostCallback
callback, Object state) at
System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc&
rpc)
Best Answer
OK - I found the answer. Very Strange, but simply put the following attribute on the WCF callback wrapper class:
Thanks to Cauldwell.net for the answer: http://www.cauldwell.net/patrick/blog/CategoryView,category,CodeGen.aspx
From cauldwell.net: