1.扫描枪获取数据原理基本相当于键盘数据,获取扫描枪扫描出来的数据,一般分为两种实现方式。
a)文本框输入获取焦点,扫描后自动显示在文本框内。
b)使用键盘钩子,勾取扫描枪虚拟按键,根据按键频率进行手动输入和扫描枪扫描判断。
2.要实现系统钩子其实很简单,调用三个Win32的API即可。
SetWindowsHookEx 用于设置钩子。(设立一道卡子,盘查需要的信息)
CallNextHookEx 用于传递钩子(消息是重要的,所以从哪里来,就应该回到哪里去,除非你决定要封锁消息)
UnhookWindowsHookEx 卸载钩子(卸载很重要,卡子设多了会造成拥堵)
版本一:
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Reflection;
using System.Diagnostics;
namespace SaomiaoTest2
{/// <summary>/// 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/// </summary>public class BardCodeHooK{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;//Ascllpublic 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;}[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, Int32 wParam, IntPtr lParam);[DllImport("user32", EntryPoint = "GetKeyNameText")]private static extern int GetKeyNameText(int IParam, 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);delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);BarCodes barCode = new BarCodes();int hKeyboardHook = 0;string strBarCode = "";private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam){if (nCode == 0){EventMsg msg = (EventMsg)Marshal.PtrToStructure(lParam, typeof(EventMsg));if (wParam == 0x100)//WM_KEYDOWN=0x100{barCode.VirtKey = msg.message & 0xff;//虚拟吗barCode.ScanCode = msg.paramL & 0xff;//扫描码StringBuilder strKeyName = new StringBuilder(225);if (GetKeyNameText(barCode.ScanCode * 65536, strKeyName, 255) > 0){barCode.KeyName = strKeyName.ToString().Trim(new char[] { ' ', '\0' });}else{barCode.KeyName = "";}byte[] 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);}TimeSpan 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;if (BarCodeEvent != null)BarCodeEvent(barCode);//触发事件barCode.IsValid = false;}}return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);}//安装钩子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);}//卸载钩子public bool Stop(){if (hKeyboardHook != 0){return UnhookWindowsHookEx(hKeyboardHook);}return true;}}
}
在实践过程中,发现版本一的代码只能扫描条形码,如伴随二维码中的字母出现就不能正确获取数据。
版本二:
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text;namespace BarcodeScanner
{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 (((TimeSpan)(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;} // 备选 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;}}
}
版本二中的代码,实践中发现出现了获取扫描数据却省略“+”加号的情况出现。
因此在版本二中备选处添加
//判断是+ 强制添加+
else if (_key.Length == 5 && msg.paramH == 0&&msg.paramL==78&&msg.message==107)
{// 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;
}
3.winform在无焦点情况下的使用方式
using BarcodeScanner;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;namespace BarCodeTest
{public partial class Form1 : Form{private ScanerHook listener = new ScanerHook(); public Form1(){InitializeComponent();listener.ScanerEvent += Listener_ScanerEvent; }private void Listener_ScanerEvent(ScanerHook.ScanerCodes codes){textBox3.Text = codes.Result; } private void Form1_Load(object sender, EventArgs e){listener.Start(); }private void Form1_FormClosed(object sender, FormClosedEventArgs e){listener.Stop(); } }
}