NullReferenceException: 未将对象引用设置到对象的实例。
StackTrace:
   在 System.Windows.Input.StylusWisp.WispTabletDeviceCollection.HandleTabletAdded(UInt32 wisptisIndex, UInt32& tabletIndexChanged)
   在 System.Windows.Input.StylusWisp.WispLogic.OnTabletAdded(UInt32 wisptisIndex)
   在 System.Windows.Input.StylusWisp.WispLogic.HandleMessage(WindowMessage msg, IntPtr wParam, IntPtr lParam)
   在 System.Windows.SystemResources.InvalidateTabletDevices(WindowMessage msg, IntPtr wParam, IntPtr lParam)
   在 System.Windows.SystemResources.SystemThemeFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   在 MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   在 MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   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)