禁用alt键临时c#

Question

我正在寻找一种在按下时禁用 alt 和 ctrl 键输入的方法。 我实际上正在开发一个宏配置器，当我按下我的宏（例如 Alt+Ctrl+NumPad0）并且我希望发送 H+E+L+L+O 键时，它不起作用，因为我按 Alt。计算机可能会尝试执行 Alt+Ctrl+H、Alt+Ctrl+E 的未知快捷方式... 所以我希望当我按下宏并且程序检测到我按下它时，它会在发送输出键时禁用临时 alt，并在完成时再次启用 Alt。 我使用 LowLevelKeyboardProc 来检测我何时按下一个键，但我无法阻止 Alt 按下，因为我实际上是在按下它来执行我的宏。

//我表单中的代码

private void Listener_OnKeyUp(object sender, KeyUpArgs e)
{
    KeyAction.RemoveKeyDown(e.KeyUp);
}


private void Listener_OnKeyPressed(object sender, KeyPressedArgs e)
{
    try
    {
        KeyAction.PutKeyDown(e.KeyPressed);
        foreach (MacroEntree macro in macros)
        {
            if (macro.Activated)
                if (macro.Action != null)
                    if (macro.isMacroDown())
                    {
                        listener.OnKeyPressed -= new EventHandler<KeyPressedArgs>(Listener_OnKeyPressed);
                        new Thread(delegate ()
                        {
                            while (IsAltCtrlDown()) ;
                            macro.ExecuteAction();
                            Thread.Sleep(100);
                            listener.OnKeyPressed += new EventHandler<KeyPressedArgs>(Listener_OnKeyPressed);

                        }).Start();
                    }
        }
    }
    catch (Exception ex)
    {

        MessageBox.Show("Erreur : " + ex.Message);
    }
}
private bool IsAltCtrlDown()
{
    if (KeyAction.isKeyDown(Key.LeftAlt) || KeyAction.isKeyDown(Key.RightAlt))
        return true;
    if (KeyAction.isKeyDown(Key.LeftCtrl) || KeyAction.isKeyDown(Key.RightCtrl))
        return true;
    return false;
}


//the code from my class that checks if the macro is down
public class KeyAction
{
   static List<Key> keyDown = new List<Key>();

    public static bool isKeyDown(Key k)
    {
        return keyDown.Contains(k);
    }
    public static void PutKeyDown(Key k)
    {
        if (!keyDown.Contains(k))
            keyDown.Add(k);
    }
    public static void RemoveKeyDown(Key k)
    {
        keyDown.Remove(k);
    }

}

Answer 1

您可以设置 low-level keyboard hook 来吞下 Windows 中的键盘输入消息。

每个本地 Windows 程序都基于所谓的message loop，基本上就是这样。

MSG msg;
while(GetMessage(&msg, NULL, 0, 0))
{ 
    TranslateMessage(&msg); 
    DispatchMessage(&msg); 
}

使用low-level keyboard hook，您可以在desktop 进程上处理此循环中的消息，并防止按键被按下。

public delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetWindowsHookEx(
    int idHook, LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);

private const int WH_KEYBOARD_LL = 13;
private static IntPtr SetHook(LowLevelKeyboardProc proc)
{
    return SetWindowsHookEx(
        WH_KEYBOARD_LL, 
        proc, 
        0, // hook on all input (https://stackoverflow.com/questions/7715480/is-zero-ever-a-valid-handle)
        0); // for all threads
}

您可以使用如下代码。当您不调用CallNextHookEx 时，按键事件不会有任何影响。

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
    IntPtr wParam, IntPtr lParam);

private const int WM_KEYDOWN = 0x0100;

private static IntPtr HookCallback(
    int nCode, IntPtr wParam, IntPtr lParam)
{
    // check if it is a key down message
    if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
    {
        int vkCode = Marshal.ReadInt32(lParam);
        // check if the pressed key is the `Alt` key
        if((Keys)vkCode == Keys.Alt)
        {
            // return 1 for handled if its the alt key
            return (IntPtr) 1; 
        }
    } 

    // let the message bubble if its not a keydown message or it wasn't the alt key which was pressed               
    return CallNextHookEx(_hookID, nCode, wParam, lParam);
}

// with this line you can set the `HookCallback` into the message loop
IntPtr hookID = SetHook(HookCallback);

别忘了解开钩子。

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool UnhookWindowsHookEx(IntPtr hhk);

UnhookWindowsHookEx(hookID);

Answer 2

感谢@Manfred Radlwimmer，我解决了这个问题。在执行我的操作之前，我发送了一个 Alt 和 Ctrl 键，它工作正常。

    private void Listener_OnKeyPressed(object sender, KeyPressedArgs e)
    {
        try
        {
            KeyAction.PutKeyDown(e.KeyPressed);
            foreach (MacroEntree macro in macros)
            {
                if (macro.Activated)
                    if (macro.Action != null)
                        if (macro.isMacroDown())
                        {
                            listener.OnKeyPressed -= new EventHandler<KeyPressedArgs>(Listener_OnKeyPressed);
                            new Thread(delegate ()
                            {
                                KeyboardOperations.SendKeyUp(KeyboardOperations.KeyCode.LALT);
                                KeyboardOperations.SendKeyUp(KeyboardOperations.KeyCode.LCONTROL);

                                macro.ExecuteAction();
                                Thread.Sleep(100);
                                listener.OnKeyPressed += new EventHandler<KeyPressedArgs>(Listener_OnKeyPressed);

                            }).Start();
                        }
            }
        }
        catch (Exception ex)
        {

            MessageBox.Show("Erreur : " + ex.Message);
        }
    }