用于测试二维码扫描仪的键盘记录

Question

我需要编写一个程序来记录来自 USB 的输入 qr/line-scanners。我必须将这个程序发送到我工作的所有办公室。该程序应收集输入信息并将文件发回进行测试。

问题是扫描仪输入很快，有些键（字符）消失了。

例如，扫描仪扫描输入字段中的“01110”，但键盘记录记录“010”。

这是我的代码

...
while (true)
{
    for (int i = 0; i < 255; i++)
    {
        int keyState = GetAsyncKeyState(i);
        if (keyState == 1 || keyState == -32767)
        {
            //log...
        }
    }
}
...

我尝试使用GetKeyState功能，在这种情况下所有的键都被记录下来，但问题是有很多重复项。例如：扫描仪“按下”零 (0) 键，但它重复了很多次，看起来像这样“000000”。

如何编写记录所有按键的键盘记录（即使输入来自 USB qr-scanner）？

Answer 1

感谢您的帮助（在评论中）。 Hooks 帮助解决了这个问题。如果有人需要，这里是解决方案。

https://docs.microsoft.com/en-us/archive/blogs/toub/low-level-keyboard-hook-in-c

using System;
using System.Diagnostics;
using System.Windows.Forms;
using System.Runtime.InteropServices;

class InterceptKeys
{
    private const int WH_KEYBOARD_LL = 13;
    private const int WM_KEYDOWN = 0x0100;
    private static LowLevelKeyboardProc _proc = HookCallback;
    private static IntPtr _hookID = IntPtr.Zero;

    public static void Main()
    {
        _hookID = SetHook(_proc);
        Application.Run();
        UnhookWindowsHookEx(_hookID);
    }

    private static IntPtr SetHook(LowLevelKeyboardProc proc)
    {
        using (Process curProcess = Process.GetCurrentProcess())
        using (ProcessModule curModule = curProcess.MainModule)
        {
            return SetWindowsHookEx(WH_KEYBOARD_LL, proc,
                GetModuleHandle(curModule.ModuleName), 0);
        }
    }

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

    private static IntPtr HookCallback(
        int nCode, IntPtr wParam, IntPtr lParam)
    {
        if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
        {
            int vkCode = Marshal.ReadInt32(lParam);
            Console.WriteLine((Keys)vkCode);
        }
        return CallNextHookEx(_hookID, nCode, wParam, lParam);
    }

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

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

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

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr GetModuleHandle(string lpModuleName);
}

用于测试二维码扫描仪的键盘记录

Keylogging for testing a qr scanner

c#

keyboard

logging