How do I darken all screen area and glow my opened window in WPF?

Question

In WPF, how do I darken all screen area when opening a new window?

Also after the window is closed, how do I revert the temporary effect?

Answer 1

You may create a background transparent window like this:

var darkwindow = new Window() {
                            Background = Brushes.Black,
                            Opacity = 0.4,
                            AllowsTransparency = true,
                            WindowStyle = WindowStyle.None,
                            WindowState = WindowState.Maximized,
                            Topmost = true
                        };
darkwindow.Show();
MessageBox.Show("Hello");
darkwindow.Close();

and replace MessageBox.Show("Hello"); with mywindow.ShowModal();. Possibly, you'll need to make mywindow always on top.

Edit

Don't use darkwindow.Hide() instead of Close().