Send keystroke to application

For TL;DR:

The goal I want to achieve is send keystroke to another application, which is the core function of my new open source application TouchAssistant. And I want the keystroke can be customized easily by configuration from user interaction.

Long Version:
  1. Use WinAPI keybd_event as this Link suggested. example as followed:
  static extern uint keybd_event(byte bVk, byte bScan, int dwFlags, int dwExtraInfo);

So far, I’m using this API, no shortcoming except no one liner to simulate keystroke with modifier.

  1. Use WinAPI SendInput as this Link suggested. Note this API is available after Vista.
  static extern uint SendInput (uint nInputs, [MarshalAs(UnmanagedType.LPArray), In] INPUT[] pInputs, int cbSize);

Much complex than previous one, however, it may get better compatibility especially with future version of Windows.

  1. Original WinForm has a method like following:

Very powerful function, and can be configured to use keybd_event or SendInput internally. However, it’s not so good to reference System.Windows.Forms in WPF application.

  1. There is an open source project Windows Input Simulator.

Good wrapper, however, cannot gain enough flexibility for user customization like AHK or SendKeys did.

  1. Integrate AHK by using