public class Window : ContentControl

Public Class Window
	Inherits ContentControl

public ref class Window : public ContentControl

type Window =  
    class
        inherit ContentControl
    end

private void ShowMessageBox(UIScreen screen, string title, string message)
{
  // ----- Create the message box.
  var text = new TextBlock
  {
    Text = message,
    Margin = new Vector4F(4),
    HorizontalAlignment = HorizontalAlignment.Center,
  };

  var button = new Button
  {
    Content = new TextBlock { Text = "Ok" },
    IsCancel = true,    // Cancel buttons are clicked when the user presses ESC (or BACK or B on the gamepad).
    IsDefault = true,   // Default buttons are clicked when the user presses ENTER or SPACE (or START or A on the gamepad).
    Margin = new Vector4F(4),
    Width = 60,
    HorizontalAlignment = HorizontalAlignment.Center,
  };

  var stackPanel = new StackPanel { Margin = new Vector4F(4) };
  stackPanel.Children.Add(text);
  stackPanel.Children.Add(button);

  var window = new Window
  {
    CanResize = false,
    IsModal = true,   // Modal dialogs consume all input until the window is closed.
    Content = stackPanel,
    MinHeight = 0,
    Title = title,
  };

  button.Click += (s, e) => window.Close();

  // ----- Show the window in the center of the screen.
  // First, we need to open the window. 
  window.Show(screen);

  // The window is now part of the visual tree of controls and can be measured. (The 
  // window does not have a fixed size. Window.Width and Window.Height are NaN. The 
  // size is calculated automatically depending on its content.)
  window.Measure(new Vector2F(float.PositiveInfinity));

  // Measure() computes DesiredWidth and DesiredHeight. With this info we can center the 
  // window on the screen.
  window.X = screen.ActualWidth / 2 - window.DesiredWidth / 2;
  window.Y = screen.ActualHeight / 2 - window.DesiredHeight / 2;
}