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：

C#类文件
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Reflection;

namespace Common
{
public 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;
}
}
}

View Code

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");
}
}
}
}