问修复InvalidOperationException时WindowsFormsHost

EN

UserControl1 control = new UserControl1();
control.AddFormsHostWithDelay(TimeSpan.FromSeconds(2));;
if (this.TryGetHandleFromName("Notepad", out IntPtr handle))
{
   HwndSourceParameters pa = new HwndSourceParameters("WPF Source", 400, 300);
   pa.ParentWindow = handle;
   pa.WindowStyle = 0x40000000 | 0x10000000; // child and visible
   pa.UsesPerPixelOpacity = false;
   pa.SetPosition(5, 5);
   HwndSource src = new HwndSource(pa);
   src.RootVisual = control;
}

'CreatorsUpdateCrashDemo.exe' (CLR v4.0.30319: 
CreatorsUpdateCrashDemo.exe): Loaded 'C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\PrivateAssemblies\Runtime\Microsoft.VisualStudio.Debugger.Runtime.dll'. 

Unhandled Exception: System.InvalidOperationException: Hosted HWND must be a child window of the specified parent.
at System.Windows.Interop.HwndHost.BuildWindow(HandleRef hwndParent)
at System.Windows.Interop.HwndHost.BuildOrReparentWindow()
at System.Windows.Interop.HwndHost.OnSourceChanged(Object sender, SourceChangedEventArgs e)

// Make sure the child window is the child of the expected parent window.
if(hwndParent.Handle != UnsafeNativeMethods.GetParent(_hwnd))
{
    throw new InvalidOperationException(SR.Get(SRID.ChildWindowMustHaveCorrectParent));
}