wpf controls - WPF - Get size of UIElement in Memory?

Question

Is there a way to get the size of a UIElement that resides in memory and has not yet been rendered?

I currently have a routine that creates a Grid from a DataTable and then adds the Grid into a FixedDocument. I need to know the size of the Grid because I want to automatically switch from Portrait to Landscape if needed; or even change the FontSize of the grid.

Answer 1

You need to force a render of the item, or wait for the item to be rendered. You can then use the ActualHeight and ActualWidth properties.

To force a render:

  MenuItem item = new MenuItem();
  item.Header = "bling";
  item.Icon = someIcon;
  //Force render
  item.Measure(new Size(Double.PositiveInfinity, Double.PositiveInfinity));
  item.Arrange(new Rect(item.DesiredSize));

In this example the MenuItem has not been given an explicit height or width. However, forcing the render will render it taking the supplied header text and icon into consideration.