C#如何将虚拟键码转换为char？

Question

我正在尝试将虚拟键码映射到char.

我的代码使用ProcessCmdKey来监听WM_KEYDOWN,这使我可以访问按下的键.例如,当我按单引号时,我得到一个222的密钥,我希望它映射到keychar 39代表...你猜对了......单引号.

我的开发上下文是: - .net Framework 2.0 - UserControl放置在很多地方

你知道问题的答案吗？

Answer 1

这不是System.Windows.Form.KeysConverter类的用途吗？

KeysConverter kc = new KeysConverter();
string keyChar = kc.ConvertToString(keyData);

Answer 2

是的,我确实使用过该MapVirtualKey方法.但我期待有关如何使用它的更多细节:使用什么DllImport指令,enum映射到字符的具体内容等.

我不喜欢这些答案,你谷歌5秒,然后只是建议一个解决方案:真正的挑战是把所有的部分放在一起,而不必浪费你的时间与大量的无样本MSDN页面或其他编码论坛为了得到你的答案.没有冒犯的基础,但是你的回答(甚至是好的)是无法解决的,因为我甚至在论坛上发布我的问题之前就得到了这个答案!

所以,你去,我将发布我正在寻找的 - 一个开箱即用的C#解决方案:

1-将此指令放在您的类中:

[DllImport("user32.dll")]
static extern int MapVirtualKey(uint uCode, uint uMapType);

2-检索你的char这样:

  protected override bool ProcessCmdKey(ref Message msg, Keys keyData)      
  {
     const int WM_KEYDOWN = 0x100;

     if (msg.Msg == WM_KEYDOWN)
     {            
        // 2 is used to translate into an unshifted character value 
        int nonVirtualKey = MapVirtualKey((uint)keyData, 2);

        char mappedChar = Convert.ToChar(nonVirtualKey);
     }

     return base.ProcessCmdKey(ref msg, keyData);
  }

感谢关心...并享受!

Answer 3

我正在寻找类似的东西,但我需要将字符映射到当前的键盘布局.由于上述答案都没有满足我的要求,这就是我想出的.

        public string KeyCodeToUnicode(Keys key)
        {
            byte[] keyboardState = new byte[255];
            bool keyboardStateStatus = GetKeyboardState(keyboardState);

            if (!keyboardStateStatus)
            {
                return "";
            }

            uint virtualKeyCode = (uint)key;
            uint scanCode = MapVirtualKey(virtualKeyCode, 0);
            IntPtr inputLocaleIdentifier = GetKeyboardLayout(0);

            StringBuilder result = new StringBuilder();
            ToUnicodeEx(virtualKeyCode, scanCode, keyboardState, result, (int)5, (uint)0, inputLocaleIdentifier);

            return result.ToString();
        }

        [DllImport("user32.dll")]
        static extern bool GetKeyboardState(byte[] lpKeyState);

        [DllImport("user32.dll")]
        static extern uint MapVirtualKey(uint uCode, uint uMapType);

        [DllImport("user32.dll")]
        static extern IntPtr GetKeyboardLayout(uint idThread);

        [DllImport("user32.dll")]
        static extern int ToUnicodeEx(uint wVirtKey, uint wScanCode, byte[] lpKeyState, [Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pwszBuff, int cchBuff, uint wFlags, IntPtr dwhkl);

Answer 4

在阅读并测试了所提供的一些答案之后,我想我会建议一个替代方案.

如MM所述,System.Windows.KeysConverter不提供键的字符表示,而是提供枚举的名称,例如"Enter"而不是'\n'.

Horas建议的MapVirtualKey方法在回答他自己的问题时是一个很好的起点,但仍然不支持大写,或者用shift键输入的字符,例如'!','$'和'>'.

我正在使用的MapVirtualKey方法的替代方法是Keys类的扩展方法:

public static char ToChar(this Keys key)
{
    char c = '\0';
    if((key >= Keys.A) && (key <= Keys.Z))
    {
        c = (char)((int)'a' + (int)(key - Keys.A));
    }

    else if((key >= Keys.D0) && (key <= Keys.D9))
    {
        c = (char)((int)'0' + (int)(key - Keys.D0));
    }

    return c;
}

上面显示的方法将提供对字母数字字符的支持.可以使用switch语句或查找表来实现对其他字符的支持.

Answer 5

我刚刚编写了Ivan Petrov 答案的改进，以在 WPF 中显示按下的按键组合的字符串表示形式，请参阅下面的代码：

public static string GetKeyString(Key key, ModifierKeys modifiers)
{
    string result = "";
    if (key != Key.None)
    {
        // Setup modifiers
        if (modifiers.HasFlag(ModifierKeys.Control))
            result += "Ctrl + ";
        if (modifiers.HasFlag(ModifierKeys.Alt))
            result += "Alt + ";
        if (modifiers.HasFlag(ModifierKeys.Shift))
            result += "Shift + ";
        // Get string representation
        string keyStr = key.ToString();
        int keyInt = (int)key;
        // Numeric keys are returned without the 'D'
        if (key >= Key.D0 && key <= Key.D9)
            keyStr = char.ToString((char)(key - Key.D0 + '0'));
        // Char keys are returned directly
        else if (key >= Key.A && key <= Key.Z)
            keyStr = char.ToString((char)(key - Key.A + 'A'));
        // If the key is a keypad operation (Add, Multiply, ...) or an 'Oem' key, P/Invoke
        else if ((keyInt >= 84 && keyInt <= 89) || keyInt >= 140)
            keyStr = KeyCodeToUnicode(key);
        result += keyStr;
    }
    return result;
}

private static string KeyCodeToUnicode(Key key)
{
    byte[] keyboardState = new byte[255];
    bool keyboardStateStatus = GetKeyboardState(keyboardState);

    if (!keyboardStateStatus)
    {
        return "";
    }

    uint virtualKeyCode = (uint)KeyInterop.VirtualKeyFromKey(key);
    uint scanCode = MapVirtualKey(virtualKeyCode, 0);
    IntPtr inputLocaleIdentifier = GetKeyboardLayout(0);

    StringBuilder result = new StringBuilder();
    ToUnicodeEx(virtualKeyCode, scanCode, new byte[255], result, (int)5, (uint)0, inputLocaleIdentifier);

    return result.ToString();
}

[DllImport("user32.dll")]
static extern bool GetKeyboardState(byte[] lpKeyState);

[DllImport("user32.dll")]
static extern uint MapVirtualKey(uint uCode, uint uMapType);

[DllImport("user32.dll")]
static extern IntPtr GetKeyboardLayout(uint idThread);

[DllImport("user32.dll")]
static extern int ToUnicodeEx(uint wVirtKey, uint wScanCode, byte[] lpKeyState, [Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pwszBuff, int cchBuff, uint wFlags, IntPtr dwhkl);