The code listed in Listing 5 creates a Button control
programmatically. First, it creates a Button object and sets its width, height,
contents, background and foreground and later the Button is added to the
LayoutRoot. 
private void CreateAButton()
{
    Button
btn = new Button();
    btn.Height = 80;
    btn.Width = 150;
    btn.Content = "Click
ME";
    btn.Background = new
SolidColorBrush(Colors.Orange);
    btn.Foreground = new
SolidColorBrush(Colors.Black);
    LayoutRoot.Children.Add(btn);
}