[转]C# Winform中无焦点状态下获取键盘输入或者USB扫描枪数据
类文件：
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Reflection;
using System.Diagnostics;
namespace Common
{
/// <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;//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;
}
[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;
}
}
}
页面中用法：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace Common
{
public partial class FrmMain : Form
{
BardCodeHooK BarCode = new BardCodeHooK();
public FrmMain()
{
InitializeComponent();
BarCode.BarCodeEvent += new BardCodeHooK.BardCodeDeletegate(BarCode_BarCodeEvent);
}
private delegate void ShowInfoDelegate(BardCodeHooK.BarCodes barCode);
private void ShowInfo(BardCodeHooK.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.Ascll.ToString();
textBox5.Text = barCode.Chr.ToString();
textBox6.Text = barCode.IsValid? barCode.BarCode : "";//是否为扫描枪输入，如果为true则是 否则为键盘输入
textBox7.Text += barCode.KeyName;
//MessageBox.Show(barCode.IsValid.ToString());
}
}
//C#中判断扫描枪输入与键盘输入
//Private DateTime _dt = DateTime.Now; //定义一个成员函数用于保存每次的时间点
//private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
//{
// DateTime tempDt = DateTime.Now; //保存按键按下时刻的时间点
// TimeSpan ts = tempDt .Subtract(_dt); //获取时间间隔
// if (ts.Milliseconds > 50) //判断时间间隔，如果时间间隔大于50毫秒，则将TextBox清空
// textBox1.Text = "";
// dt = tempDt ;
//}
void BarCode_BarCodeEvent(BardCodeHooK.BarCodes barCode)
{
ShowInfo(barCode);
}
private void FrmMain_Load(object sender, EventArgs e)
{
BarCode.Start();
}
private void FrmMain_FormClosed(object sender, FormClosedEventArgs e)
{
BarCode.Stop();
}
private void textBox6_TextChanged(object sender, EventArgs e)
{
if (textBox6.Text.Length > 0)
{
MessageBox.Show("条码长度：" + textBox6.Text.Length + "\n条码内容：" + textBox6.Text, "系统提示");
}
}
}
}
