F#でキーボードフック

C#でできるらしいので、F#でもできるだろうということでやってみました。
.Net上の言語でキーボードフックしてるプログラムを載せてる色々なWebページを参考にしました。

F#のコンソールにコピペしてhook_start関数を実行すると,PrintScreenをフックするようになります。

open System

open System.Diagnostics

open System.Runtime.InteropServices



[<Literal>]

let WH_KEYBOARD_LL = 13



[<Literal>]

let HC_ACTION = 0



[<Literal>]

let WM_KEYDOWN = 0x0100



[<Literal>]

let WM_KEYUP = 0x0101



[<Literal>]

let WM_SYSKEYDOWN = 0x0104



[<Literal>]

let WM_SYSKEYUP = 0x0105



[<Literal>]

let VK_SNAPSHOT = 0x2Cu



[<StructLayout(LayoutKind.Sequential)>]

type KBDLLHOOKSTRUCT =

  val vkCode : uint32

  val scanCode : uint32

  val flags : uint32

  val time : uint32

  val dwExtraInfo : uint32



type LowLevelKeyboardProc = delegate of int * nativeint * KBDLLHOOKSTRUCT ->\

nativeint



[<DllImport("kernel32.dll")>]

extern uint32 GetCurrentThreadId()



[<DllImport("kernel32.dll", SetLastError = true)>]

extern nativeint GetModuleHandle(string lpModuleName)



[<DllImport("user32.dll", SetLastError = true)>]

extern bool UnhookWindowsHookEx(nativeint hhk)



[<DllImport("user32.dll", SetLastError = true)>]

extern nativeint SetWindowsHookEx(int idhook, LowLevelKeyboardProc proc, native\

int hMod, uint32 threadId)



[<DllImport("user32.dll", SetLastError = true)>]

extern nativeint CallNextHookEx(nativeint hHook, int nCode, nativeint wParam, K\

BDLLHOOKSTRUCT lParam)



let mutable s_hook = 0n



let SetHook (proc : LowLevelKeyboardProc) =

  use curProc = Process.GetCurrentProcess()

  use curMod = curProc.MainModule

  s_hook <- SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curMod.\

ModuleName), 0u)

  if s_hook = 0n then false else true



let UnSetHook () =

  if s_hook <> 0n then

      if UnhookWindowsHookEx(s_hook) then

          s_hook <- 0n

          true

      else

          false

  else

      false



let MyHookProc (nCode : int) (wParam : nativeint) (lParam : KBDLLHOOKSTRUCT) =

  if nCode = HC_ACTION then

      match (int wParam, lParam.vkCode) with

      | (WM_KEYDOWN, VK_SNAPSHOT)  -> printf "Print Screen\n"; 1\

n

      | (_, _) -> CallNextHookEx(s_hook, nCode, wParam, lParam)

  else

      CallNextHookEx(s_hook, nCode, wParam, lParam)



let hook_start() = SetHook(new LowLevelKeyboardProc(MyHookProc))