You can monitor keyboard and mouse activity in the background with the Nuget package MouseKeyHook (GitHub).
This code detects when a key is pressed:
private IKeyboardMouseEvents _globalHook;
private void Subscribe()
{
if (_globalHook == null)
{
// Note: for the application hook, use the Hook.AppEvents() instead
_globalHook = Hook.GlobalEvents();
_globalHook.KeyPress += GlobalHookKeyPress;
}
}
private static void GlobalHookKeyPress(object sender, KeyPressEventArgs e)
{
Console.WriteLine("KeyPress: \t{0}", e.KeyChar);
}
private void Unsubscribe()
{
if (_globalHook != null)
{
_globalHook.KeyPress -= GlobalHookKeyPress;
_globalHook.Dispose();
}
}
You will need to call Subscribe() to start listening, and Unsubscribe() to stop listening. Obviously you need to modify GlobalHookKeyPress() to do useful work.
I needed this functionality in order to write a utility which will turn on the keyboard backlight on a Lenovo Thinkpad when any key is pressed, including CTRL (which KeyPress doesn't catch). For this purpose, I had to monitor for key down instead. The code is the same except we attach to a different event...
_globalHook.KeyDown += GlobalHookOnKeyDown;
and the event handler signature is different:
private static void GlobalHookOnKeyDown(object sender, KeyEventArgs e)
{
Console.WriteLine("KeyDown: \t{0}", e.KeyCode);
}
The library can also detect specific key combinations and sequences. For example:
Hook.GlobalEvents().OnCombination(new Dictionary<Combination, Action>
{
{ Combination.TriggeredBy(Keys.A).Control(), () => { Console.WriteLine("You Pressed CTRL+A"); } },
{ Combination.FromString("Shift+Alt+Enter"), () => { Console.WriteLine("You Pressed FULL SCREEN"); } }
});
