类型的已垃圾回收委托进行了回调。这可能会导致应用程序崩溃、损坏和数据丢失。向非托管代码传递委托时，托管应用程序必须让这些委托保持活动状态，直到确信不会再次调用它们的问题的解决方法 续集

接上文

今天突然发现键盘控制不行了，结果还是那个问题搞的鬼，原以为解决了，但是紧接着问题又来了，汗颜啊，将钩子封装成dll

前台调用实例如下

CHW.HookHelper hook;  //钩子

<span style="font-family:Microsoft YaHei;font-size:18px;"><span style="font-family:Microsoft YaHei;font-size:18px;">private void MainForm_Activated(object sender, EventArgs e)
        {
            //注册事件
            hook = new CHW.HookHelper();
            hook.SetHook();
            hook.OnKeyDownEvent += new KeyEventHandler(hook_OnKeyDownEvent);
            hook.OnKeyUpEvent += new KeyEventHandler(hook_OnKeyUpEvent);
        }</span></span>

<span style="font-family:Microsoft YaHei;font-size:18px;"><pre name="code" class="csharp">private void MainForm_Leave(object sender, EventArgs e)
        {
            //注销钩子事件
            hook.UnHook();
        }
void hook_OnKeyUpEvent(object sender, KeyEventArgs e)
        {
            if (chkbAllowKeyboard.Checked)
            {
                //按了左键  按了右键  按了上键  按了下键 之后放起操作
                if (e.KeyCode == Keys.Left || e.KeyCode == Keys.Right || e.KeyCode == Keys.Up || e.KeyCode == Keys.Down)
                    btn_MouseUp(sender, null);
            }
        }

        /// <summary>
        /// 钩子程序控制，键盘作用
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void hook_OnKeyDownEvent(object sender, KeyEventArgs e)
        {
            if (chkbAllowKeyboard.Checked)
            {
                if (e.KeyCode == Keys.Left)
                {
                    //按下左键
                    btnLeft.Focus();
                    btnLeft_MouseDown(sender, null);
                }
                if (e.KeyCode == Keys.Right)
                {
                    //按下右键
                    btnRight.Focus();
                    btnRight_MouseDown(sender, null);
                }
                if (e.KeyCode == Keys.Up)
                {
                    //按下上键
                    btnFront.Focus();
                    btnFront_MouseDown(sender, null);
                }
                if (e.KeyCode == Keys.Down)
                {
                    //按下下键
                    btnBack.Focus();
                    btnBack_MouseDown(sender, null);
                }
            }
        }
</span>

然后经过一般搜索查找，方法如下：

<span style="font-family:Microsoft YaHei;font-size:18px;"><pre name="code" class="csharp">private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
        {
            try
            {
                //如果该消息被丢弃（nCode<0）或者没有事件绑定处理程序则不会触发事件
                if ((nCode >= 0) && (OnKeyDownEvent != null || OnKeyUpEvent != null || OnKeyPressEvent != null))
                {
                    KeyboardHookStruct KeyDataFromHook = (KeyboardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyboardHookStruct));
                    Keys keyData = (Keys)KeyDataFromHook.vkCode;

                    //按下控制键
                    if ((OnKeyDownEvent != null || OnKeyPressEvent != null) && (wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN))
                    {
                        if (IsCtrlAltShiftKeys(keyData) && preKeysList.IndexOf(keyData) == -1)
                            preKeysList.Add(keyData);
                    }

                    //WM_KEYDOWN和WM_SYSKEYDOWN消息，将会引发OnKeyDownEvent事件
                    if (OnKeyDownEvent != null && (wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN))
                    {
                        KeyEventArgs e = new KeyEventArgs(GetDownKeys(keyData));

                        OnKeyDownEvent(this, e);
                    }

                    //WM_KEYDOWN消息将引发OnKeyPressEvent
                    if (OnKeyPressEvent != null && wParam == WM_KEYDOWN)
                    {
                        byte[] keyState = new byte[256];
                        GetKeyboardState(keyState);
                        byte[] inBuffer = new byte[2];
                        if (ToAscii(KeyDataFromHook.vkCode, KeyDataFromHook.scanCode, keyState, inBuffer, KeyDataFromHook.flags) == 1)
                        {
                            KeyPressEventArgs e = new KeyPressEventArgs((char)inBuffer[0]);
                            OnKeyPressEvent(this, e);
                        }
                    }

                    //松开控制键
                    if ((OnKeyDownEvent != null || OnKeyPressEvent != null) && (wParam == WM_KEYUP || wParam == WM_SYSKEYUP))
                    {
                        if (IsCtrlAltShiftKeys(keyData))
                        {
                            for (int i = preKeysList.Count - 1; i >= 0; i--)
                            {
                                if (preKeysList[i] == keyData)
                                    preKeysList.RemoveAt(i);
                            }
                        }
                    }

                    //WM_KEYUP和WM_SYSKEYUP消息，将引发OnKeyUpEvent事件
                    if (OnKeyUpEvent != null && (wParam == WM_KEYUP || wParam == WM_SYSKEYUP))
                    {
                        KeyEventArgs e = new KeyEventArgs(GetDownKeys(keyData));
                        OnKeyUpEvent(this, e);
                    }
                }

               <strong> return CallNextHookEx(hHook, nCode, wParam, lParam);
                //调用下一个钩子函数，如果返回非0，就是丢弃该消息，此时windows不会处理该消息</strong>
                //return 0;
            }
            catch (Exception)
            {
                return 0;
            }
        }
目前测试在Win7+VS2010调试会报错，运行编译后文件没有问题，在XP+VS2010下调试会报错，运行编译后文件没有问题</span>

</pre><pre name="code" class="csharp"><span style="font-family:Microsoft YaHei;font-size:18px;">如果将上述修改为：return 0;则不会出问题，此时只有一个钩子的话就没有问题，如果有多个钩子大于2个以上就会有问题了</span>

</pre><p><span style="font-family:Microsoft YaHei;font-size:18px;"></span></p><p><span style="font-family:Microsoft YaHei;font-size:18px;">上篇文章代码中出现问题的部分代码改成源代码如下：</span></p><p><pre name="code" class="csharp"><span style="font-family:Microsoft YaHei;font-size:18px;">public void SetHook()
        {
            //KeyboardHookDelegate = KeyboardHookProc;
            KeyboardHookDelegate = new HookProc(KeyboardHookProc);
            Process cProcess = Process.GetCurrentProcess();
            ProcessModule cModule = cProcess.MainModule;
            IntPtr intPtr = GetModuleHandle(cModule.ModuleName);
            hHook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyboardHookDelegate, intPtr, 0);
            if (hHook == 0)
            {
                UnHook();
                //throw new Exception(Marshal.GetLastWin32Error().ToString());
            }
        }</span>