本文所述实例为C#结合数据库，来验证所识别的ID卡内容，通过本实例代码，用户可以轻松实现对ID卡会员信息的验证。该实例代码可实现读取数据库，进而逐步实现数据库连接，数据库读取，ID卡读取，ID卡信息与数据库内容比对，最终返回结果并告之是否验证成功。

具体功能代码如下：

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;

using System.Data.OleDb;

using System.Runtime.InteropServices;

using System.Diagnostics;

using System.Collections;

namespace IDCard

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

public delegate int HookProc(int nCode, int wParam, IntPtr lParam);

static int hHook = 0;

public const int WH_KEYBOARD_LL = 13;

//LowLevel键盘截获，如果是WH_KEYBOARD＝2，并不能对系统键盘截取，Acrobat Reader会在你截取之前获得键盘。

HookProc KeyBoardHookProcedure;

[DllImport("kernel32")]

public static extern int Beep(int dwFreq, int dwDuration);//让计算机蜂鸣

string DataPath = "";//数据库路径

OleDbConnection con;//OleDbConnection对象，连接数据库

OleDbCommand cmd;//OleDbCommand对象，执行SQL语句

//键盘Hook结构函数

[StructLayout(LayoutKind.Sequential)]

public class KeyBoardHookStruct

{

public int vkCode;

public int scanCode;

public int flags;

public int time;

public int dwExtraInfo;

}

[DllImport("user32.dll")]

public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);

[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]

//抽掉钩子

public static extern bool UnhookWindowsHookEx(int idHook);

[DllImport("user32.dll")]

//调用下一个钩子

public static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);

[DllImport("kernel32.dll")]

public static extern IntPtr GetModuleHandle(string name);

public string getNum(string code)

{

string flag = "";

switch (code)

{

case "048":

flag="0"; break;

case "049":

flag = "1"; break;

case "050":

flag = "2"; break;

case "051":

flag = "3"; break;

case "052":

flag = "4"; break;

case "053":

flag = "5"; break;

case "054":

flag = "6"; break;

case "055":

flag = "7"; break;

case "056":

flag = "8"; break;

case "057":

flag = "9"; break;

}

return flag;

}

public void Hook_Start()

{

// 安装键盘钩子

if (hHook == 0)

{

KeyBoardHookProcedure = new HookProc(KeyBoardHookProc);

hHook = SetWindowsHookEx(WH_KEYBOARD_LL,

KeyBoardHookProcedure,

GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), 0);

//如果设置钩子失败.

if (hHook == 0)

{

Hook_Clear();

}

}

}

//取消钩子事件

public void Hook_Clear()

{

bool retKeyboard = true;

if (hHook != 0)

{

retKeyboard = UnhookWindowsHookEx(hHook);

hHook = 0;

}

//如果去掉钩子失败.

if (!retKeyboard) throw new Exception("UnhookWindowsHookEx failed.");

}

//这里可以添加自己想要的信息处理

string NumCode="";

public int KeyBoardHookProc(int nCode, int wParam, IntPtr lParam)

{

if (nCode >= 0)

{

if (wParam == 0x0104 || wParam == 0x0100)

{

KeyBoardHookStruct kbh = (KeyBoardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyBoardHookStruct));

int flag = kbh.vkCode;

switch (flag)

{

case 96:

NumCode += "0"; break;

case 97:

NumCode += "1"; break;

case 98:

NumCode += "2"; break;

case 99:

NumCode += "3"; break;

case 100:

NumCode += "4"; break;

case 101:

NumCode += "5"; break;

case 102:

NumCode += "6"; break;

case 103:

NumCode += "7"; break;

case 104:

NumCode += "8"; break;

case 105:

NumCode += "9"; break;

}

if (flag == 13)

{

if (NumCode.Length != 0)

{

string c = "";

string id = "";

for (int i = 0; i <= NumCode.Length - 3; i += 3)

{

string b = NumCode.Substring(i, 3);

c += getNum(b);

}

id = c;

if (id.Length == 8)//如果卡号为8位

{

//实例化OleDbConnection对象

con = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + DataPath);

con.Open();//打开数据库连接

//实例化OleDbCommand对象，根据ID卡号检索数据表

cmd = new OleDbCommand("select * from tb_UserInfo where CardID='" + id + "'", con);

OleDbDataReader sdr = cmd.ExecuteReader();//实例化OleDbDataReader对象

sdr.Read();//读取记录

txtShowCardID.Text = id;//获取ID卡号

txtShowName.Text = sdr["UName"].ToString();//获取员工姓名

cbbShowSex.Text = sdr["USex"].ToString();//获取员工性别

cbbShowDep.Text = sdr["UDep"].ToString();//获取员工部门

con.Close();//关闭数据库连接

Beep(3000, 100);//计算机蜂鸣

}

NumCode = "";

}

}

}

}

return CallNextHookEx(hHook, nCode, wParam, lParam);

}

private void Form1_Load(object sender, EventArgs e)

{

cbbdep.SelectedIndex = 0;//设置部门下拉框的第一项被选中

cbbsex.SelectedIndex = 0;//设置性别下拉框的第一项被选中

//获取数据库路径

DataPath = Application.StartupPath.ToString();

DataPath = DataPath.Substring(0, DataPath.LastIndexOf("\\"));

DataPath = DataPath.Substring(0, DataPath.LastIndexOf("\\"));

DataPath += @"\db.mdb";

}

private void radioButton1_CheckedChanged(object sender, EventArgs e)

{

if (radioButton1.Checked)

{

groupBox1.Enabled = true;

Hook_Clear();

}

}

private void radioButton2_CheckedChanged(object sender, EventArgs e)

{

if (radioButton2.Checked)

{

groupBox1.Enabled = false;

Hook_Start();

}

}

private void button2_Click(object sender, EventArgs e)

{

txtIdcard.Text = "";

txtName.Text = "";

}

private void button1_Click(object sender, EventArgs e)

{

if (txtIdcard.Text == "" || txtName.Text == "")//如果没有输入ID卡号和员工姓名

{

//弹出警告信息

if (MessageBox.Show("请将数据填写完整！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Error) == DialogResult.OK)

{

if (txtIdcard.Text == "")//如果没有输入ID卡号

txtIdcard.Focus();//则光标处在输入ID卡号的文本框

if (txtName.Text == "")//如果没有输入员工姓名

txtName.Focus();//则光标处在输入员工姓名的文本框

if (txtIdcard.Text == "" && txtName.Text == "")//如果都没输入数据

txtIdcard.Focus();//则光标处在输入ID卡号的文本框

}

}

else//如果输入了数据

{

if (txtIdcard.Text.Trim().Length != 8)//如果输入的ID卡号不是8位

{

//弹出警告信息

if (MessageBox.Show("ID卡号必须为8位！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Error) == DialogResult.OK)

{

txtIdcard.Text = "";//清空输入ID卡号的文本框

txtIdcard.Focus();//让光标处在输入ID卡号的文本框上

}

}

else//如果输入的ID卡号为8位

{

//实例化OleDbConnection对象

con=new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + DataPath);

con.Open();//打开连接

//实例化OleDbCommand对象

cmd = new OleDbCommand("select count(*) from tb_UserInfo where CardID='"+txtIdcard.Text.Trim()+"'", con);

int flag =Convert.ToInt32(cmd.ExecuteScalar());//判断是否已经添加过此ID卡号

if (flag > 0)//如果大于0则说明已经添加过

{

//弹出警告信息

if (MessageBox.Show("ID卡号已经添加过了！", "警告", MessageBoxButtons.OK, MessageBoxIcon.Error) == DialogResult.OK)

{

button2_Click(sender, e);//清空输入ID卡号和员工姓名的文本框

}

}

else//如果小于0说明没有添加过

{

//实例化OleDbCommand对象

cmd = new OleDbCommand("insert into tb_UserInfo(CardID,UName,USex,UDep) values ('" + txtIdcard.Text.Trim() + "','" + txtName.Text.Trim() + "','" + cbbsex.Text.Trim() + "','" + cbbdep.Text.Trim() + "')", con);

int k = cmd.ExecuteNonQuery();//执行insert语句，将输入的信息添加到数据库中

if (k > 0)//如果大于0则操作成功

{

//弹出提示信息

if (MessageBox.Show("添加成功！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information) == DialogResult.OK)

{

button2_Click(sender, e);//清空输入ID卡号和员工姓名的文本框

}

}

}

con.Close();//关闭数据库连接

}

}

}

private void txtIdcard_KeyPress(object sender, KeyPressEventArgs e)

{

if (!(e.KeyChar <= '9' && e.KeyChar >= '0') && e.KeyChar != '\r' && e.KeyChar != '\b')

{

e.Handled = true;

}

}

}

}

该实例注释完善，便于阅读，读者还可以根据自身需求改善代码，或者添加新的功能以满足自身应用的个性化需求。