 <p>Do you mean that the form shall exchange its contents with a message plus an OK button? </p> <p>This would be similar to the way a text mode interface typically works.</p> <p>You can make it happen by adding a disabled panel or UserControl with message and button topmost on the form and enable it when you wish to alert the user. However, I am puzzled how to implement the blocking behavior similar to MessageBox.Show() and Dialog.Show().</p>