VSTO应用程序中加入键盘钩子

在VSTO应用程序中有时为了处理一些快捷按键操作等实现一些特殊的功能，此时需要对键盘进行挂钩，此时使用P/Invoke函数实现，参考如下：

VSTO加载和卸载时进行钩子的初始化和卸载

  KeyboardHook hook;
        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
           hook = new KeyboardHook();
            hook.InitHook();
        }
 
        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
            hook.UnHook();
        }
    }
 //钩子具体处理逻辑是：
    class KeyboardHook
    {
        #region (invokestuff)
        [DllImport("kernel32.dll")]
        static extern uint GetCurrentThreadId();
        [DllImport("user32.dll")]
        static extern IntPtr SetWindowsHookEx(int code, HookProcKeyboard func, IntPtr hInstance, uint threadID);
        [DllImport("user32.dll")]
        static extern bool UnhookWindowsHookEx(IntPtr hhk);
        [DllImport("user32.dll")]
        static extern int CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);
        #endregion
 
        #region constans
        private const int WH_KEYBOARD = 2;
        private const int HC_ACTION = 0;
        #endregion
 
        delegate int HookProcKeyboard(int code, IntPtr wParam, IntPtr lParam);
        private HookProcKeyboard KeyboardProcDelegate = null;
        private IntPtr khook;
        bool doing = false;
 
        public void InitHook()
        {
            uint id = GetCurrentThreadId();
            //init the keyboard hook with the thread id of the Visual Studio IDE   
            this.KeyboardProcDelegate = new HookProcKeyboard(this.KeyboardProc);
            khook = SetWindowsHookEx(WH_KEYBOARD, this.KeyboardProcDelegate, IntPtr.Zero, id);
        }
 
        public void UnHook()
        {
            if (khook != IntPtr.Zero)
            {
                UnhookWindowsHookEx(khook);
            }
        }
 
       private int KeyboardProc(int code, IntPtr wParam, IntPtr lParam)
        {
            try
            {
                if (code != HC_ACTION)
                {
                    return CallNextHookEx(khook, code, wParam, lParam);
                }
 
                if ((int)wParam == (int)Keys.Z && ((int)lParam & (int)Keys.Alt) != 0)
                {
                    if (!doing)
                    {
                        doing = true;
                        MessageBox.Show("Captured");
                        doing = false;
                    }
                }
            }
            catch
            {
            }
 
            return CallNextHookEx(khook, code, wParam, lParam);
        }
    }