在 C#/Windows 窗体中检测应用程序启动时的 shift 键答案

【问题标题】：Detect shift key on application startup in C#/Windows Forms在 C#/Windows 窗体中检测应用程序启动时的 shift 键
【发布时间】：2010-11-01 08:15:41
【问题描述】：

有没有办法让标准的 Windows 窗体应用程序检测是否在应用程序启动时按住了 Shift 键 - 而不使用 Windows 挂钩？

如果在运行 EXE 文件时按住 shift 键，我希望工作流程能够从正常状态改变。

【问题讨论】：

标签： c# winforms detect hotkeys shift

【解决方案1】：

ModifierKeys 属性看起来很理想：

private void Form1_Load(object sender, EventArgs e)
{
    if ( (ModifierKeys & Keys.Shift) != 0)
    {
      MessageBox.Show("Shift is pressed");
    }
}

【讨论】：

【解决方案2】：

我意识到这已经很老了，但看到人们为此苦苦挣扎，我有点困扰。 ModifierKeys 是一个位域，因此依靠 .ToString() 或 == 来查看是否按下了 Shift 键，充其量是不可靠的，并且不是位域的正确使用：

public enum ModifierKeys
{
    /// <summary>No modifiers are pressed.</summary>
    None = 0,

    /// <summary>The ALT key.</summary>
    Alt = 1,

    /// <summary>The CTRL key.</summary>
    Control = 2,

    /// <summary>The SHIFT key.</summary>
    Shift = 4,

    /// <summary>The Windows logo key.</summary>
    // Windows = 8, No longer leaked
}

可能没有按下 Alt、Control 或 Shift 的任意组合或任何组合，因此检查应为：

if ((ModifierKeys & Keys.Shift) != 0)
{
    MessageBox.Show("Shift is pressed");
}

只要我获得这样做的权利，我就会对 Dan 的回答投赞成票 :-) .Net 4+ 也包括 HasFlag() 方法，但我习惯于按位运算，所以我没有使用它.有关按位运算、标志、（带有）真值表和其他花絮的更多信息，请参阅：

http://geekswithblogs.net/BlackRabbitCoder/archive/2010/07/22/c-fundamentals-combining-enum-values-with-bit-flags.aspx

你在源代码中看到的更有趣：

/// <devdoc>
///     Retrieves the current state of the modifier keys. This will check the
///     current state of the shift, control, and alt keys.
/// </devdoc>
public static Keys ModifierKeys {
    get {
        Keys modifiers = 0;
        // SECURITYNOTE : only let state of Shift-Control-Alt out...
        //
        if (UnsafeNativeMethods.GetKeyState((int)Keys.ShiftKey) < 0) modifiers |= Keys.Shift;
        if (UnsafeNativeMethods.GetKeyState((int)Keys.ControlKey) < 0) modifiers |= Keys.Control;
        if (UnsafeNativeMethods.GetKeyState((int)Keys.Menu) < 0) modifiers |= Keys.Alt;
        return modifiers;
    }
}

此实现仅发出 Shift、Control 和 Alt 的状态。不包括 Windows 的键状态。

如果您想在创建表单或控件之前检测键状态，也许在 Main() 方法中，您可能会发疯。

也许你想这样做：

if (VirtualKeyState.VK_SHIFT.IsKeyPressed())
{
    Debugger.Launch();
}

创建一个简单的扩展方法：

public static class KeyAssist
{
    public const int KEY_PRESSED = 0x8000;

    public static bool IsKeyPressed(this VirtualKeyState key) => Convert.ToBoolean(Native.GetKeyState(key) & KEY_PRESSED);
}

进口：

[DllImport("user32.dll")]
public static extern short GetKeyState(VirtualKeyState virtualKeyState);

创建以下枚举（如果您愿意，也可以创建一些小节）（来自 PInvoke）：

public enum VirtualKeyState
{

    VK_LBUTTON = 0x01,
    VK_RBUTTON = 0x02,
    VK_CANCEL = 0x03,
    VK_MBUTTON = 0x04,
    VK_XBUTTON1 = 0x05,
    VK_XBUTTON2 = 0x06,
    VK_BACK = 0x08,
    VK_TAB = 0x09,
    VK_CLEAR = 0x0C,
    VK_RETURN = 0x0D,
    VK_SHIFT = 0x10,
    VK_CONTROL = 0x11,
    VK_MENU = 0x12,
    VK_PAUSE = 0x13,
    VK_CAPITAL = 0x14,
    VK_KANA = 0x15,
    VK_HANGEUL = 0x15,           
    VK_HANGUL = 0x15,
    VK_JUNJA = 0x17,
    VK_FINAL = 0x18,
    VK_HANJA = 0x19,
    VK_KANJI = 0x19,
    VK_ESCAPE = 0x1B,
    VK_CONVERT = 0x1C,
    VK_NONCONVERT = 0x1D,
    VK_ACCEPT = 0x1E,
    VK_MODECHANGE = 0x1F,
    VK_SPACE = 0x20,
    VK_PRIOR = 0x21,
    VK_NEXT = 0x22,
    VK_END = 0x23,
    VK_HOME = 0x24,
    VK_LEFT = 0x25,
    VK_UP = 0x26,
    VK_RIGHT = 0x27,
    VK_DOWN = 0x28,
    VK_SELECT = 0x29,
    VK_PRINT = 0x2A,
    VK_EXECUTE = 0x2B,
    VK_SNAPSHOT = 0x2C,
    VK_INSERT = 0x2D,
    VK_DELETE = 0x2E,
    VK_HELP = 0x2F,
    VK_LWIN = 0x5B,
    VK_RWIN = 0x5C,
    VK_APPS = 0x5D,
    VK_SLEEP = 0x5F,
    VK_NUMPAD0 = 0x60,
    VK_NUMPAD1 = 0x61,
    VK_NUMPAD2 = 0x62,
    VK_NUMPAD3 = 0x63,
    VK_NUMPAD4 = 0x64,
    VK_NUMPAD5 = 0x65,
    VK_NUMPAD6 = 0x66,
    VK_NUMPAD7 = 0x67,
    VK_NUMPAD8 = 0x68,
    VK_NUMPAD9 = 0x69,
    VK_MULTIPLY = 0x6A,
    VK_ADD = 0x6B,
    VK_SEPARATOR = 0x6C,
    VK_SUBTRACT = 0x6D,
    VK_DECIMAL = 0x6E,
    VK_DIVIDE = 0x6F,
    VK_F1 = 0x70,
    VK_F2 = 0x71,
    VK_F3 = 0x72,
    VK_F4 = 0x73,
    VK_F5 = 0x74,
    VK_F6 = 0x75,
    VK_F7 = 0x76,
    VK_F8 = 0x77,
    VK_F9 = 0x78,
    VK_F10 = 0x79,
    VK_F11 = 0x7A,
    VK_F12 = 0x7B,
    VK_F13 = 0x7C,
    VK_F14 = 0x7D,
    VK_F15 = 0x7E,
    VK_F16 = 0x7F,
    VK_F17 = 0x80,
    VK_F18 = 0x81,
    VK_F19 = 0x82,
    VK_F20 = 0x83,
    VK_F21 = 0x84,
    VK_F22 = 0x85,
    VK_F23 = 0x86,
    VK_F24 = 0x87,
    VK_NUMLOCK = 0x90,
    VK_SCROLL = 0x91,
    VK_OEM_NEC_EQUAL = 0x92,        
    VK_OEM_FJ_JISHO = 0x92,     
    VK_OEM_FJ_MASSHOU = 0x93,          
    VK_OEM_FJ_TOUROKU = 0x94,      
    VK_OEM_FJ_LOYA = 0x95,      
    VK_OEM_FJ_ROYA = 0x96,      
    VK_LSHIFT = 0xA0,
    VK_RSHIFT = 0xA1,
    VK_LCONTROL = 0xA2,
    VK_RCONTROL = 0xA3,
    VK_LMENU = 0xA4,
    VK_RMENU = 0xA5,
    VK_BROWSER_BACK = 0xA6,
    VK_BROWSER_FORWARD = 0xA7,
    VK_BROWSER_REFRESH = 0xA8,
    VK_BROWSER_STOP = 0xA9,
    VK_BROWSER_SEARCH = 0xAA,
    VK_BROWSER_FAVORITES = 0xAB,
    VK_BROWSER_HOME = 0xAC,
    VK_VOLUME_MUTE = 0xAD,
    VK_VOLUME_DOWN = 0xAE,
    VK_VOLUME_UP = 0xAF,
    VK_MEDIA_NEXT_TRACK = 0xB0,
    VK_MEDIA_PREV_TRACK = 0xB1,
    VK_MEDIA_STOP = 0xB2,
    VK_MEDIA_PLAY_PAUSE = 0xB3,
    VK_LAUNCH_MAIL = 0xB4,
    VK_LAUNCH_MEDIA_SELECT = 0xB5,
    VK_LAUNCH_APP1 = 0xB6,
    VK_LAUNCH_APP2 = 0xB7,
    VK_OEM_1 = 0xBA,      
    VK_OEM_PLUS = 0xBB,      
    VK_OEM_COMMA = 0xBC,      
    VK_OEM_MINUS = 0xBD,      
    VK_OEM_PERIOD = 0xBE,      
    VK_OEM_2 = 0xBF,      
    VK_OEM_3 = 0xC0,      
    VK_OEM_4 = 0xDB,      
    VK_OEM_5 = 0xDC,      
    VK_OEM_6 = 0xDD,      
    VK_OEM_7 = 0xDE,      
    VK_OEM_8 = 0xDF,
    VK_OEM_AX = 0xE1,         
    VK_OEM_102 = 0xE2,          
    VK_ICO_HELP = 0xE3,       
    VK_ICO_00 = 0xE4,       
    VK_PROCESSKEY = 0xE5,
    VK_ICO_CLEAR = 0xE6,
    VK_PACKET = 0xE7,
    VK_OEM_RESET = 0xE9,
    VK_OEM_JUMP = 0xEA,
    VK_OEM_PA1 = 0xEB,
    VK_OEM_PA2 = 0xEC,
    VK_OEM_PA3 = 0xED,
    VK_OEM_WSCTRL = 0xEE,
    VK_OEM_CUSEL = 0xEF,
    VK_OEM_ATTN = 0xF0,
    VK_OEM_FINISH = 0xF1,
    VK_OEM_COPY = 0xF2,
    VK_OEM_AUTO = 0xF3,
    VK_OEM_ENLW = 0xF4,
    VK_OEM_BACKTAB = 0xF5,
    VK_ATTN = 0xF6,
    VK_CRSEL = 0xF7,
    VK_EXSEL = 0xF8,
    VK_EREOF = 0xF9,
    VK_PLAY = 0xFA,
    VK_ZOOM = 0xFB,
    VK_NONAME = 0xFC,
    VK_PA1 = 0xFD,
    VK_OEM_CLEAR = 0xFE
}

不管怎样，这只是作为参考，所以没有太多的猜测。

HTH，

科尔比

【讨论】：

【解决方案3】：

检查 Control.ModifierKeys ...

    [STAThread]
    static void Main(string[] args)
    {
        if (Control.ModifierKeys == Keys.ShiftKey)
        {
            // Do something special
        }
    }

【讨论】：

我无法让您的解决方案发挥作用。 @Dan 的位测试版本确实有效。
我在使用调试器时无法正常工作（Control.ModifierKeys 在启动期间始终为 None），但是当我从Windows 资源管理器，同时按住 Shift 键。

【解决方案4】：

我知道这篇文章已经很老了，但我遇到了这个问题并通过修改 Jamie 的代码来解决它：

[STAThread]
static void Main(string[] args)
{
    if (Control.ModifierKeys.ToString() == "Shift")
    {
        // Do something special
    }
}

【讨论】：

【解决方案5】：

Here is an article 关于直接读取按键状态（和鼠标）。

【讨论】：

快速描述或提示如何操作会很好。该网址给了我'504 Gateway Timeout - Gateway timeout expired while waiting server response'