从使用Raw Input API检索的按键集合中获取字符串

Question

我正在使用Raw Input API从键盘(实际上是模拟键盘的磁条卡读卡器)获取按键的集合.这里有几个代码摘录,所以你可以知道我是如何获得密钥的.

[StructLayout(LayoutKind.Sequential)]
internal struct RAWKEYBOARD
{
    [MarshalAs(UnmanagedType.U2)]
    public ushort MakeCode;
    [MarshalAs(UnmanagedType.U2)]
    public ushort Flags;
    [MarshalAs(UnmanagedType.U2)]
    public ushort Reserved;
    [MarshalAs(UnmanagedType.U2)]
    public ushort VKey;
    [MarshalAs(UnmanagedType.U4)]
    public uint Message;
    [MarshalAs(UnmanagedType.U4)]
    public uint ExtraInformation;
}

[StructLayout(LayoutKind.Explicit)]
internal struct RAWINPUT
{
    [FieldOffset(0)]
    public RAWINPUTHEADER header;
    [FieldOffset(16)]
    public RAWMOUSE mouse;
    [FieldOffset(16)]
    public RAWKEYBOARD keyboard;
    [FieldOffset(16)]
    public RAWHID hid;
}

Queue<char> MyKeys = new Queue<char>();

// buffer has the result of a GetRawInputData() call
RAWINPUT raw = (RAWINPUT)Marshal.PtrToStructure(buffer, typeof(RAWINPUT));
MyKeys.Enqueue((char)raw.keyboard.VKey);

运行代码时,读卡器输出字符串%B40^TEST,但在MyKeys集合中,我有以下值:

{ 16 '',  53 '5', 16 '', 66 'B',
  52 '4', 48 '0', 16 '', 54 '6',
  16 '',  84 'T', 16 '', 69 'E',
  16 '',  83 'S', 16 '', 84 'T' }

这些似乎是实际按键(duh!)的集合,而不是它们代表的字符串.键码16似乎是Shift,因此在读卡器当前配置的键盘映射%中,使用Shift + 5生成一个字符,由{16,53}表示.以下字符大写B为Shift + B或{16,66}.所以它适用于其他角色.

显然,简单地将它们投射到char(就像我现在正在做的那样)并不是要走的路.所以,我的问题是:如何将这个按键数组转换为它们代表的字符串？

Answer 1

在做了一些额外的研究之后,我自己找到了答案.我正在为其他读这篇文章的人发帖.以下是一个小型测试应用程序,演示如何将虚拟键(ushort键代码)的集合转换为其字符串表示形式.我正在使用问题中描述的集合作为输入.

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

    [DllImport("user32.dll")]
    private static extern int ToAscii(uint uVirtKey, uint uScanCode, byte[] lpKeyState, [Out] StringBuilder lpChar, uint uFlags);

    static void Main(string[] args)
    {
        byte[] keyState = new byte[256];
        ushort[] input = { 16, 53, 16, 66, 52, 48, 16, 54, 16, 84, 16, 69, 16, 83, 16, 84 };
        StringBuilder output = new StringBuilder();

        foreach (ushort vk in input)
            AppendChar(output, vk, ref keyState);

        Console.WriteLine(output);
        Console.ReadKey(true);
    }

    private static void AppendChar(StringBuilder output, ushort vKey, ref byte[] keyState)
    {
        if (MapVirtualKey(vKey, 2) == 0)
        {
            keyState[vKey] = 0x80;
        }
        else
        {
            StringBuilder chr = new StringBuilder(2);
            int n = ToAscii(vKey, 0, keyState, chr, 0);
            if (n > 0)
                output.Append(chr.ToString(0, n));

            keyState = new byte[256];
        }
    }
}