// Create the Panel DockPanel
dp1 = new DockPanel();
// Create a Text Control and then set its Dock property
txt1 = new TextBlock();
DockPanel.SetDock(txt1, System.Windows.Controls.Dock.Top);
txt1.Text = "The Dock Property is set to " + DockPanel.GetDock(txt1);
dp1.Children.Add(txt1);
mainWindow.Content = dp1;
mainWindow.Show();