Key-chording, simultaneously pressing multiple keys to create a UI gesture, has been a part of the Windows UI language since the early days. It is a powerful way to pack a load of functionality into a sparse UI.
The Windows App SDK supports limited chording with both keyboard and pointer events. When a keyboard key is pressed or released you also have direct access to the state of the Menu key (KeyRoutedEventArgs.KeyStatus.IsMenuKeyDown). When a pointer is pressed or released you also get the state of the Control, Menu, Shift and Windows keys via the KeyModifiers property of the PointerRoutedEventArgs.
This repo contains a small chunk of reusable C# code, User32KeyboardHelper that extends these build-in capabilities by allowing you to get the state of any key at any time.
In the Win32 world, the USER32.dll contains two functions that provide direct keyboard access:
GetKeyState(int nVirtKey)returns the state of the single specified key.GetKeyboardState([out] lpKeyState)returns a byte array describing the state of every key.
The VirtualKey enumeration exists in the Windows App SDK (WinRT) world. It defines unique integer values for the commonly used keyboard, mouse, and gamepad keys. Cast it to an int, and a VirtualKey value exactly maps to the int needed for GetKeyState. And that int can also be used as an index into the array of key state values returned by GetKeyboardState.
User32KeyboardHelper wraps GetKeyState and GetKeyboardState in methods that accept (GetKeyState) or return (GetKeyboardState) VirtualKey values. It also provides convienece functions for chording multiple keys.
To tryout keyboard chording, press A and S and then either B, to turn the window background blue, or R to turn it red. Tryout mouse chording by first pressing one or more keyboard keys and then one of your mouse button.