"The specified Visual is not an ancestor of this Visual" exception in OxySKElement.OnRender() #1787
Description
Description
We use a docking manager in our application. With it it's possible to dock out windows with plots and arrange them on another screens.
With the current oxyplot version and OxyPlot.SkiaSharp.Wpf.PlotView, we get an exception after undocking a window with a plot.
Partial stack-trace:
System.InvalidOperationException
HResult=0x80131509
Message=The specified Visual is not an ancestor of this Visual.
Source=PresentationCore
StackTrace:
at System.Windows.Media.Visual.TrySimpleTransformToAncestor(Visual ancestor, Boolean inverse, GeneralTransform& generalTransform, Matrix& simpleTransform)
at System.Windows.Media.Visual.TransformToAncestor(Visual ancestor)
at OxyPlot.SkiaSharp.Wpf.OxySKElement.OnRender(DrawingContext drawingContext)
at System.Windows.UIElement.Arrange(Rect finalRect)
at System.Windows.Controls.Grid.ArrangeOverride(Size arrangeSize)
at System.Windows.FrameworkElement.ArrangeCore(Rect finalRect)
at System.Windows.UIElement.Arrange(Rect finalRect)
...
[Call Stack Truncated]
This exception was originally thrown at this call stack:
System.Windows.Media.Visual.TrySimpleTransformToAncestor(System.Windows.Media.Visual, bool, out System.Windows.Media.GeneralTransform, out System.Windows.Media.Matrix)
System.Windows.Media.Visual.TransformToAncestor(System.Windows.Media.Visual)
OxyPlot.SkiaSharp.Wpf.OxySKElement.OnRender(System.Windows.Media.DrawingContext)
System.Windows.UIElement.Arrange(System.Windows.Rect)
System.Windows.Controls.Grid.ArrangeOverride(System.Windows.Size)
System.Windows.FrameworkElement.ArrangeCore(System.Windows.Rect)
System.Windows.UIElement.Arrange(System.Windows.Rect)
System.Windows.Controls.Border.ArrangeOverride(System.Windows.Size)
System.Windows.FrameworkElement.ArrangeCore(System.Windows.Rect)
System.Windows.UIElement.Arrange(System.Windows.Rect)
...
[Call Stack Truncated]
Steps to reproduce
- Use a docking manager like syncfusion DockingManger
- Undock the window with the plot, so that the window with the PlotView is no longer a descendant of the MainWindow in the VisualTree .
VisualTree of the Application with floating window:
Platform: x86 & x64
.NET version: 4.7.2
Latest OxyPlot Version (nuget packages build from develop brunch)
Actual behaviour
The call Window.GetWindow(this) in OxySKElement.OnRender() returns always the MainWindow. I think it uses the logical tree not the visual tree and this.TransformToAncestor() fails, because the MainWindow is actually not an ancestor of the plot in case of a floating window.
Possible Fix
Get the ancestor from the visual tree with a methode like this
private Window GetAncestorWindowFromVisualTree(DependencyObject startElement)
{
DependencyObject parent = startElement;
while (!(parent is Window))
{
if (parent == null) { break; }
parent = VisualTreeHelper.GetParent(parent);
}
return parent as Window ?? Window.GetWindow(this);
}
var visualOffset = this.TransformToAncestor(GetAncestorWindowFromVisualTree(this)).Transform(default);