C#结合数据库实现验证识别ID卡内容的方法

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。