Transparent Window (or Draw to screen) No Mouse Capture

Question

In an app I\'m coding I would like to make an alert message to appear that displays a large semi-transparent warning message without affecting the users work. Basically I w

Answer 1

Override the CreateParams property on your Form class and make sure the WS_EX_NOACTIVATE extended style is set. Mine looks like this:

protected override CreateParams CreateParams
{
  get
  {
    CreateParams baseParams = base.CreateParams;

    baseParams.ExStyle |= ( int )(
      Win32.ExtendedWindowStyles.WS_EX_LAYERED |
      Win32.ExtendedWindowStyles.WS_EX_TRANSPARENT |
      Win32.ExtendedWindowStyles.WS_EX_NOACTIVATE |
      Win32.ExtendedWindowStyles.WS_EX_TOOLWINDOW );

    return baseParams;
  }
}

Values for ExtendedWindowStyles used above are:

WS_EX_LAYERED = 0x00080000,
WS_EX_NOACTIVATE = 0x08000000,
WS_EX_TOOLWINDOW = 0x00000080,
WS_EX_TRANSPARENT = 0x00000020,