// This routine handles the following cases:
// 1) a parent window is present, build the child window
// 2) a parent is present, reparent the child window to it
// 3) a parent window is not present, hide the child window by parenting it to SystemResources.Hwnd window.
private void BuildOrReparentWindow()
{
DemandIfUntrusted();
// Verify the thread has access to the context.
// VerifyAccess();
// Prevent reentry while building a child window,
// also prevent the reconstruction of Disposed objects.
if (_isBuildingWindow || _isDisposed)
{
return;
}
_isBuildingWindow = true;
// Find the source window, this must be the parent window of
// the child window.
IntPtr hwndParent = IntPtr.Zero;
PresentationSource source = PresentationSource.CriticalFromVisual(this, false /* enable2DTo3DTransition */);
if (source != null)
{
HwndSource hwndSource = source as HwndSource;
if (hwndSource != null)
{
hwndParent = hwndSource.CriticalHandle;
}
}
else
{
// attempt to also walk through 3D - if we get a non-null result then we know we are inside of
// a 3D scene which is not supported
PresentationSource goingThrough3DSource = PresentationSource.CriticalFromVisual(this, true /* enable2DTo3DTransition */);
if (goingThrough3DSource != null)
{
if (TraceHwndHost.IsEnabled)
{
TraceHwndHost.Trace(TraceEventType.Warning, TraceHwndHost.HwndHostIn3D);
}
}
}
try
{
if (hwndParent != IntPtr.Zero)
{
if (_hwnd.Handle == IntPtr.Zero)
{
// We now have a parent window, so we can create the child
// window.
BuildWindow(new HandleRef(null, hwndParent));
this.LayoutUpdated += _handlerLayoutUpdated;
this.IsEnabledChanged += _handlerEnabledChanged;
this.IsVisibleChanged += _handlerVisibleChanged;
}
else if (hwndParent != UnsafeNativeMethods.GetParent(_hwnd))
{
// We have a different parent window. Just reparent the
// child window under the new parent window.
UnsafeNativeMethods.SetParent(_hwnd, new HandleRef(null, hwndParent));
}
}
else
{
// Reparent the window to notification-only window provided by SystemResources
// This keeps the child window around, but it is not visible. We can reparent the
// window later when a new parent is available
var hwnd = SystemResources.GetDpiAwarenessCompatibleNotificationWindow(_hwnd);
UnsafeNativeMethods.SetParent(_hwnd, new HandleRef(null, hwnd.Handle));
// ...But we have a potential problem: If the SystemResources listener window gets
// destroyed ahead of the call to HwndHost.OnDispatcherShutdown(), the HwndHost's window
// will be destroyed too, before the "logical" Dispose has had a chance to do proper
// shutdown. This turns out to be very significant for WebBrowser/ActiveXHost, which shuts
// down the hosted control through the COM interfaces, and the control destroys its
// window internally. Evidently, the WebOC fails to do full, proper cleanup if its
// window is destroyed unexpectedly.
// To avoid this situation, we make sure SystemResources responds to the Dispatcher
// shutdown event after this HwndHost.
SystemResources.DelayHwndShutdown();
}
}
finally
{
// Be careful to clear our guard bit.
_isBuildingWindow = false;
}
}
private void BuildOrReparentWindow()
{
this.DemandIfUntrusted();
if (this._isBuildingWindow || this._isDisposed)
{
return;
}
this._isBuildingWindow = true;
IntPtr intPtr = IntPtr.Zero;
PresentationSource presentationSource = PresentationSource.CriticalFromVisual(this, false);
if (presentationSource != null)
{
HwndSource hwndSource = presentationSource as HwndSource;
if (hwndSource != null)
{
intPtr = hwndSource.CriticalHandle;
}
}
else
{
PresentationSource presentationSource2 = PresentationSource.CriticalFromVisual(this, true);
if (presentationSource2 != null && TraceHwndHost.IsEnabled)
{
TraceHwndHost.Trace(TraceEventType.Warning, TraceHwndHost.HwndHostIn3D);
}
}
try
{
if (intPtr != IntPtr.Zero)
{
if (this._hwnd.Handle == IntPtr.Zero)
{
this.BuildWindow(new HandleRef(null, intPtr));
base.LayoutUpdated += this._handlerLayoutUpdated;
base.IsEnabledChanged += this._handlerEnabledChanged;
base.IsVisibleChanged += this._handlerVisibleChanged;
}
else if (intPtr != UnsafeNativeMethods.GetParent(this._hwnd))
{
UnsafeNativeMethods.SetParent(this._hwnd, new HandleRef(null, intPtr));
}
}
else
{
IntPtr value = (!FrameworkAppContextSwitches.DisableDevDiv1035544) ? this.Handle : this._hwnd.Handle;
if (value != IntPtr.Zero)
{
HwndWrapper dpiAwarenessCompatibleNotificationWindow = SystemResources.GetDpiAwarenessCompatibleNotificationWindow(this._hwnd);
if (dpiAwarenessCompatibleNotificationWindow != null)
{
UnsafeNativeMethods.SetParent(this._hwnd, new HandleRef(null, dpiAwarenessCompatibleNotificationWindow.Handle));
SystemResources.DelayHwndShutdown();
}
else
{
Trace.WriteLineIf(dpiAwarenessCompatibleNotificationWindow == null, string.Format("- Warning - Notification Window is null\n{0}", new StackTrace(true).ToString()));
}
}
}
}
finally
{
this._isBuildingWindow = false;
}
}