C#实现扫描枪扫描二维码并打印(实例代码)-创新互联

1.使用usb口输入的扫描枪，这里实现使用了winform

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首先创建一个CS文件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
namespace am_sign
{
 class BardCodeHooK
 {
  public delegate void BardCodeDeletegate(BarCodes barCode);
  public event BardCodeDeletegate BarCodeEvent;
  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
   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);
  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)
     {
      strBarCode = barCode.Chr.ToString();
     }
     else
     {
      if ((msg.message & 0xff) == 13 && strBarCode.Length > 3)
      {
       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)
   {
    //WH_KEYBOARD_LL=13
    hKeyboardHook = SetWindowsHookEx(13, new HookProc(KeyboardHookProc), Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);
   }
   return (hKeyboardHook != 0);
  }
  //卸载钩子
  public bool Stop()
  {
   if (hKeyboardHook != 0)
   {
    return UnhookWindowsHookEx(hKeyboardHook);
   }
   return true;
  }
 }
}

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