Layout measurement override of element should not return NaN values as its DesiredSize

I've run into a similar issue when I try to call Measure and pass the dynamically calculated size to that method:

Layout measurement override of element 'System.Windows.Controls.StackPanel' should not return NaN values as its DesiredSize.

I am trying to create a StackPanel on the fly and print it. Here's my code:

StackPanel printPanel = new StackPanel();

PrintableArea.Children.Remove(ChartBorder);
printPanel.Children.Add(ChartBorder);

//Get selected printer capabilities
System.Printing.PrintCapabilities capabilities = dialog.PrintQueue.GetPrintCapabilities(dialog.PrintTicket);

//Get scale of the print wrt to screen of visual
double scale = Math.Min(capabilities.PageImageableArea.ExtentWidth / printPanel.ActualWidth, capabilities.PageImageableArea.ExtentHeight / printPanel.ActualHeight);

//Transform the Visual to scale
printPanel.LayoutTransform = new ScaleTransform(scale, scale);

/开发者_JAVA技巧/Get the size of the printer page
Size sz = new Size(capabilities.PageImageableArea.ExtentWidth, capabilities.PageImageableArea.ExtentHeight);

//Update the layout of the visual to the printer page size.
printPanel.Measure(sz);
printPanel.Arrange(new Rect(new Point(capabilities.PageImageableArea.OriginWidth, capabilities.PageImageableArea.OriginHeight), sz));

dialog.PrintVisual(printPanel, "Test");

Any clue what could be the cause of this? And the strange thing is this happens only with StackPanel. If I try to create a simple TextBlock for testing purpose and try to print that, everything works fine with no errors. I was wondering what's different when we call Measure for StackPanel?

Any help to fix this issue would be really great!

Your are probably passing in Size(double.NaN, double.NaN) to the Measure call, which is bad. Your printPanel.ActualWidth/ActualHeight should be 0.0, which results in NaN. This is how Double defines NaN:

   public const double NaN = (double) 0.0 / (double) 0.0;

So you would need to pass in Size(double.PositiveInfinity, double.PositiveInfinity) to get the desired size. After you arrange the printPanel, the ActualWidth/ActualHeight should be valid.