Programmatically changing the “presentation display mode”

Question

The presentation display modes are those you see when using the Windows+p shortcut:

1. Computer Only
2. Duplicate

Answer 1

In case the EnumDisplaySettingsEx and ChangeDisplaySettingsEx functions do not work for you, you can also use this:

        private void SetDisplayMode(DisplayMode mode)
        {
            var proc = new Process();
            proc.StartInfo.FileName = "DisplaySwitch.exe";
            switch (mode)
            {
                case DisplayMode.External:
                    proc.StartInfo.Arguments = "/external";
                    break;
                case DisplayMode.Internal:
                    proc.StartInfo.Arguments = "/internal";
                    break;
                case DisplayMode.Extend:
                    proc.StartInfo.Arguments = "/extend";
                    break;
                case DisplayMode.Duplicate:
                    proc.StartInfo.Arguments = "/clone";
                    break;
            }
            proc.Start();
        }
        enum DisplayMode
        {
            Internal,
            External,
            Extend,
            Duplicate
        }

This will call the DisplaySwitcher with different arguments based on the required configuration. You can thus call:

   SetDisplayMode(DisplayMode.Extend);