摘自网络，测试可用
public class ScanerHook
{
public delegate void ScanerDelegate(ScanerCodes codes);
public event ScanerDelegate ScanerEvent;
//private const int WM_KEYDOWN = 0x100;//KEYDOWN
//private const int WM_KEYUP = 0x101;//KEYUP
//private const int WM_SYSKEYDOWN = 0x104;//SYSKEYDOWN
//private const int WM_SYSKEYUP = 0x105;//SYSKEYUP
//private static int HookProc(int nCode, Int32 wParam, IntPtr lParam);
private int hKeyboardHook = 0;//声明键盘钩子处理的初始值
private ScanerCodes codes = new ScanerCodes();//13为键盘钩子
//定义成静态，这样不会抛出回收异常
private static HookProc hookproc;
delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
//设置钩子
private static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
//卸载钩子
private static extern bool UnhookWindowsHookEx(int idHook);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
//继续下个钩子
private static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);
[DllImport("user32", EntryPoint = "GetKeyNameText")]
private static extern int GetKeyNameText(int IParam, StringBuilder lpBuffer, int nSize);
[DllImport("user32", EntryPoint = "GetKeyboardState")]
//获取按键的状态
private static extern int GetKeyboardState(byte[] pbKeyState);
[DllImport("user32", EntryPoint = "ToAscii")]
//ToAscii职能的转换指定的虚拟键码和键盘状态的相应字符或字符
private static extern bool ToAscii(int VirtualKey, int ScanCode, byte[] lpKeySate, ref uint lpChar, int uFlags);
//int VirtualKey //[in] 指定虚拟关键代码进行翻译。
//int uScanCode, // [in] 指定的硬件扫描码的关键须翻译成英文。高阶位的这个值设定的关键，如果是（不压）
//byte[] lpbKeyState, // [in] 指针，以256字节数组，包含当前键盘的状态。每个元素（字节）的数组包含状态的一个关键。如果高阶位的字节是一套，关键是下跌（按下）。在低比特，如/果设置表明，关键是对切换。在此功能，只有肘位的CAPS LOCK键是相关的。在切换状态的NUM个锁和滚动锁定键被忽略。
//byte[] lpwTransKey, // [out] 指针的缓冲区收到翻译字符或字符。
//uint fuState); // [in] Specifies whether a menu is active. This parameter must be 1 if a menu is active, or 0 otherwise.
[DllImport("kernel32.dll")]
//使用WINDOWS API函数代替获取当前实例的函数,防止钩子失效
public static extern IntPtr GetModuleHandle(string name);
public ScanerHook()
{
}
public bool Start()
{
if (hKeyboardHook == 0)
{
hookproc = new HookProc(KeyboardHookProc);
//GetModuleHandle 函数 替代 Marshal.GetHINSTANCE
//防止在 framework4.0中 注册钩子不成功
IntPtr modulePtr = GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName);
//WH_KEYBOARD_LL=13
//全局钩子 WH_KEYBOARD_LL
// hKeyboardHook = SetWindowsHookEx(13, hookproc, Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);
hKeyboardHook = SetWindowsHookEx(13, hookproc, modulePtr, 0);
}
return (hKeyboardHook != 0);
}
public bool Stop()
{
if (hKeyboardHook != 0)
{
bool retKeyboard = UnhookWindowsHookEx(hKeyboardHook);
hKeyboardHook = 0;
return retKeyboard;
}
return true;
}
private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
{
EventMsg msg = (EventMsg)Marshal.PtrToStructure(lParam, typeof(EventMsg));
codes.Add(msg);
if (ScanerEvent != null && msg.message == 13 && msg.paramH > 0 && !string.IsNullOrEmpty(codes.Result))
{
ScanerEvent(codes);
}
return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);
}
public class ScanerCodes
{
private int ts = 100; // 指定输入间隔为300毫秒以内时为连续输入
private List<List<EventMsg>> _keys = new List<List<EventMsg>>();
private List<int> _keydown = new List<int>(); // 保存组合键状态
private List<string> _result = new List<string>(); // 返回结果集
private DateTime _last = DateTime.Now;
private byte[] _state = new byte[256];
private string _key = string.Empty;
private string _cur = string.Empty;
public EventMsg Event
{
get
{
if (_keys.Count == 0)
{
return new EventMsg();
}
else
{
return _keys[_keys.Count - 1][_keys[_keys.Count - 1].Count - 1];
}
}
}
public List<int> KeyDowns
{
get
{
return _keydown;
}
}
public DateTime LastInput
{
get
{
return _last;
}
}
public byte[] KeyboardState
{
get
{
return _state;
}
}
public int KeyDownCount
{
get
{
return _keydown.Count;
}
}
public string Result
{
get
{
if (_result.Count > 0)
{
return _result[_result.Count - 1].Trim();
}
else
{
return null;
}
}
}
public string CurrentKey
{
get
{
return _key;
}
}
public string CurrentChar
{
get
{
return _cur;
}
}
public bool isShift
{
get
{
return _keydown.Contains(160);
}
}
public void Add(EventMsg msg)
{
#region 记录按键信息
// 首次按下按键
if (_keys.Count == 0)
{
_keys.Add(new List<EventMsg>());
_keys[0].Add(msg);
_result.Add(string.Empty);
}
// 未释放其他按键时按下按键
else if (_keydown.Count > 0)
{
_keys[_keys.Count - 1].Add(msg);
}
// 单位时间内按下按键
else if ((DateTime.Now - _last).TotalMilliseconds < ts)
{
_keys[_keys.Count - 1].Add(msg);
}
// 从新记录输入内容
else
{
_keys.Add(new List<EventMsg>());
_keys[_keys.Count - 1].Add(msg);
_result.Add(string.Empty);
}
#endregion
_last = DateTime.Now;
#region 获取键盘状态
// 记录正在按下的按键
if (msg.paramH == 0 && !_keydown.Contains(msg.message))
{
_keydown.Add(msg.message);
}
// 清除已松开的按键
if (msg.paramH > 0 && _keydown.Contains(msg.message))
{
_keydown.Remove(msg.message);
}
#endregion
#region 计算按键信息
int v = msg.message & 0xff;
int c = msg.paramL & 0xff;
StringBuilder strKeyName = new StringBuilder(500);
if (GetKeyNameText(c * 65536, strKeyName, 255) > 0)
{
_key = strKeyName.ToString().Trim(new char[] { ' ', '\0' });
GetKeyboardState(_state);
if (_key.Length == 1 && msg.paramH == 0)// && msg.paramH == 0
{
// 根据键盘状态和shift缓存判断输出字符
_cur = ShiftChar(_key, isShift, _state).ToString();
_result[_result.Count - 1] += _cur;
}
else if (_key.Length == 5 && msg.paramH == 0 && msg.paramL == 78 && msg.message == 107)// && msg.paramH == 0
{
// 根据键盘状态和shift缓存判断输出字符
_cur = Convert.ToChar('+').ToString();
_result[_result.Count - 1] += _cur;
}
else
{
_cur = string.Empty;
}
}
#endregion
}
private char ShiftChar(string k, bool isShiftDown, byte[] state)
{
bool capslock = state[0x14] == 1;
bool numlock = state[0x90] == 1;
bool scrolllock = state[0x91] == 1;
bool shiftdown = state[0xa0] == 1;
char chr = (capslock ? k.ToUpper() : k.ToLower()).ToCharArray()[0];
if (isShiftDown)
{
if (chr >= 'a' && chr <= 'z')
{
chr = (char)((int)chr - 32);
}
else if (chr >= 'A' && chr <= 'Z')
{
if (chr == 'Z')
{
string s = "";
}
chr = (char)((int)chr + 32);
}
else
{
string s = "`1234567890-=[];',./";
string u = "~!@#$%^&*()_+{}:\"<>?";
if (s.IndexOf(chr) >= 0)
{
return (u.ToCharArray())[s.IndexOf(chr)];
}
}
}
return chr;
}
}
public struct EventMsg
{
public int message;
public int paramL;
public int paramH;
public int Time;
public int hwnd;
}
}
某些情况下，特别是使用类似像微软拼音之类的中文输入法时，扫码枪会出现字符被输入法截获，显示不是很友好，所以需要使用InputMethod.SetPreferredImeState(target, InputMethodState.Off)来关闭输入法，只能输入英文，待业务调用完成后再切换回来。target可以是业务的主界面窗口，也可以是foucus的输入框。