C# 无焦点状态下获取键盘输入或者USB扫描枪数据
使用示例：
private readonly BardCodeHooK _barCode = new BardCodeHooK();
private void InitBarcode() {
_barCode.BarCodeEvent += OnBarcode;
_barCode.Start();
}
private void OnBarcode(BardCodeHooK.BarCodes barCode) {
if (!barCode.IsValid) return;
var str = barCode.BarCode.Replace("\0", "");
Console.WriteLine($"{DateTime.Now:MM:dd HH:mm:ss.fff} [{str}]");
}
键盘钩子类
///
/// 键盘钩子
///
public class BardCodeHooK {
#region 定义
//获取键盘输入或者USB扫描枪数据 可以是没有焦点 应为使用的是全局钩子USB扫描枪 是模拟键盘按下这里主要处理扫描枪的值，手动输入的值不太好处理
public delegate void BardCodeDeletegate(BarCodes barCode);
public event BardCodeDeletegate BarCodeEvent;
//定义成静态，这样不会抛出回收异常
private static HookProc _hookproc;
public struct BarCodes {
public int VirtKey;//虚拟吗
public int ScanCode;//扫描码
public string KeyName;//键名
public uint Ascll;//Ascll
public char Chr;//字符
public string BarCode;//条码信息 保存最终的条码
public bool IsValid;//条码是否有效
public DateTime Time;//扫描时间,
}
private struct EventMsg {
public int message;
public int paramL;
public int paramH;
public int Time;
public int hwnd;
}
private delegate int HookProc(int nCode, int wParam, IntPtr lParam);
private BarCodes _barCode;
private int _hKeyboardHook;
private string _strBarCode = "";
#endregion
public bool Start() {
if (_hKeyboardHook != 0) return _hKeyboardHook != 0;
_hookproc = KeyboardHookProc;
var modulePtr = GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName);
_hKeyboardHook = SetWindowsHookEx(13, _hookproc, modulePtr, 0);
return (_hKeyboardHook != 0);
}
public bool Stop() {
return _hKeyboardHook == 0 || UnhookWindowsHookEx(_hKeyboardHook);
}
private int KeyboardHookProc(int nCode, int wParam, IntPtr lParam) {
if (nCode != 0) return CallNextHookEx(_hKeyboardHook, nCode, wParam, lParam);
var msg = (EventMsg)Marshal.PtrToStructure(lParam, typeof(EventMsg));
if (wParam != 0x100) return CallNextHookEx(_hKeyboardHook, nCode, wParam, lParam);
_barCode.VirtKey = msg.message & 0xff;//虚拟吗
_barCode.ScanCode = msg.paramL & 0xff;//扫描码
var strKeyName = new StringBuilder(225);
_barCode.KeyName = GetKeyNameText(_barCode.ScanCode * 65536, strKeyName, 255) > 0 ? strKeyName.ToString().Trim(' ', '\0') : "";
var kbArray = new byte[256];
uint uKey = 0;
GetKeyboardState(kbArray);
if (ToAscii(_barCode.VirtKey, _barCode.ScanCode, kbArray, ref uKey, 0)) {
_barCode.Ascll = uKey;
_barCode.Chr = Convert.ToChar(uKey);
}
var ts = DateTime.Now.Subtract(_barCode.Time);
if (ts.TotalMilliseconds > 50) {//时间戳，大于50 毫秒表示手动输入
_strBarCode = _barCode.Chr.ToString();
} else {
if ((msg.message & 0xff) == 13 && _strBarCode.Length > 3) {//回车
_barCode.BarCode = _strBarCode;
_barCode.IsValid = true;
}
_strBarCode += _barCode.Chr.ToString();
}
_barCode.Time = DateTime.Now;
BarCodeEvent?.Invoke(_barCode);//触发事件
_barCode.IsValid = false;
return CallNextHookEx(_hKeyboardHook, nCode, wParam, lParam);
}
#region DllImport
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern bool UnhookWindowsHookEx(int idHook);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);
[DllImport("user32", EntryPoint = "GetKeyNameText")]
private static extern int GetKeyNameText(int param, StringBuilder lpBuffer, int nSize);
[DllImport("user32", EntryPoint = "GetKeyboardState")]
private static extern int GetKeyboardState(byte[] pbKeyState);
[DllImport("user32", EntryPoint = "ToAscii")]
private static extern bool ToAscii(int virtualKey, int scanCode, byte[] lpKeySate, ref uint lpChar, int uFlags);
[DllImport("kernel32.dll")]
public static extern IntPtr GetModuleHandle(string name);
#endregion
}