COMException
   在 MS.Win32.UnsafeNativeMethods.ITfSource.UnadviseSink(Int32 cookie)
   在 System.Windows.Documents.TextServicesHost.OnUnregisterTextStore(Object arg)
   在 System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   在 System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)