红外条码扫描器的另类使用C 版

               

     3年前写了一篇《USB口的红外条形码扫描器的另类使用》，不过相关代码是VB编写，在这几年之间，有许多网友提出需要C#版的，起初还以为由VB修改C#应该很容易，最近研究了一下，发现C#和VB调用API的机制还是有所不同的，在迁移的过程中还是会遇到不少问题，所以我专门抽时间做了一个基于C#的程序。

      【目前的条形码扫描器有点类似外接键盘（其实从消息传送上它就相当于一个键盘），把输入焦点定位到可输入的控件上，一扫描相应的条形码信息就输入到文本框中去了，但是如果没有输入焦点，或另一个不相干的程序获得输入焦点，那就有点乱套了。我想实现的是，不管什么情况，只要扫描器一工作，我的程序就能自动**，并能获得当前输入的条形码信息。 实现思路：我用的是litele牌的USB口的红外条形码扫描器，仔细分析了一下，扫描成功后，以键盘按键消息的形式把条形码输入信息通知给系统。这样通过键盘钩子就可以方便的获得该信息了。但是，怎样区分信息是键盘还是条形码输入的哪？很简单，条形码扫描器在很短的时间内输入了至少3个字符以上信息，并且以“回车”作为结束字符，在这种思想指引下，很完美的实现了预定功能。】

     VB相关的代码请见：http://blog.****.net/yefanqiu/archive/2006/08/30/1144881.aspx

    

    

 

 

---

 

窗体相关代码：

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;namespace ReadBadCode{    public partial class frmTest : Form    {        BarCodeHook BarCode = new BarCodeHook();        public frmTest()        {            InitializeComponent();            BarCode.BarCodeEvent += new BarCodeHook.BarCodeDelegate(BarCode_BarCodeEvent);        }        private delegate void ShowInfoDelegate(BarCodeHook.BarCodes barCode);        private void ShowInfo(BarCodeHook.BarCodes barCode)        {            if (this.InvokeRequired)            {                this.BeginInvoke(new ShowInfoDelegate(ShowInfo), new object[] { barCode });            }            else            {                textBox1.Text = barCode.KeyName;                textBox2.Text = barCode.VirtKey.ToString();                textBox3.Text = barCode.ScanCode.ToString();                textBox4.Text = barCode.AscII.ToString();                textBox5.Text = barCode.Chr.ToString();                textBox6.Text = barCode.IsValid ? barCode.BarCode : "";            }        }        void BarCode_BarCodeEvent(BarCodeHook.BarCodes barCode)        {            ShowInfo(barCode);        }        private void frmTest_Load(object sender, EventArgs e)        {            BarCode.Start();        }        private void frmTest_FormClosed(object sender, FormClosedEventArgs e)        {            BarCode.Stop();        }        private void textBox6_TextChanged(object sender, EventArgs e)        {            if (textBox6.Text.Length > 0)            {                MessageBox.Show(textBox6.Text);            }        }    }} 

 

BarCodeHook 类：

using System;using System.Collections.Generic;using System.Text;using System.Runtime.InteropServices;using System.Reflection;namespace ReadBadCode{    public class BarCodeHook    {        public delegate void BarCodeDelegate(BarCodes barCode);        public event BarCodeDelegate BarCodeEvent;        public struct BarCodes        {            public int VirtKey;      //虚拟码            public int ScanCode;     //扫描码            public string KeyName;   //键名            public uint AscII;       //AscII            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 lParam, 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[] lpKeyState, 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;  //虚拟码                    barCode.ScanCode = msg.paramL & 0xff;  //扫描码                    StringBuilder strKeyName = new StringBuilder(255);                    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.AscII = uKey;                        barCode.Chr = Convert.ToChar(uKey);                    }                    if (DateTime.Now.Subtract(barCode.Time).TotalMilliseconds > 50)                     {                        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)            {                //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;        }    }}

    

 【注意】和VB程序不同，要想测试实际的效果，必须执行编译后的Exe文件，在开发环境直接运行会没有效果的。