Win32Exception: 无效的窗口句柄。
--NativeErrorCode: 1400
StackTrace:
   在 Standard.NativeMethods.GetWindowPlacement(IntPtr hwnd)
   在 System.Windows.Shell.WindowChromeWorker._GetHwndState()
   在 System.Windows.Shell.WindowChromeWorker._UpdateSystemMenu(Nullable`1 assumeState)
   在 System.Windows.Shell.WindowChromeWorker._HandleWindowPosChanged(WM uMsg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   在 System.Windows.Shell.WindowChromeWorker._WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   在 System.Windows.Interop.HwndSource.PublicHooksFilterMessage(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)