【转】c#怎么连接数据库 用MySQL 详解

1、mysql官网下载 .net连接器

2、引用下载后的mysql.data.dll

3、程序开始加：using MySql.Data.MySqlClient;

4、连接数据库：

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private void button1_Click(object sender, EventArgs e)//登入按钮         {             string power = comboBox1.Text.Trim();             string user = textBox1.Text.Trim();             string psd = textBox2.Text.Trim();             string ipaddress = "";             string mysqluser = "";             string mysqlpsd = "";               if (user == "")             {                 MessageBox.Show("请输入用户名");             }             else if (psd == "")             {                 MessageBox.Show("请输入密码");             }             else             {                 try                 {                     try                     {                         string[] getconfig = File.ReadAllLines("E:/project/configure.txt", Encoding.GetEncoding("gb2312"));                         ipaddress = getconfig[0].Split(':')[1];//读取ip地址                         mysqluser = getconfig[1].Split(':')[1];//读取数据库账号                         mysqlpsd = getconfig[2].Split(':')[1]; //读取数据库密码                            }                     catch (Exception)                     {                         MessageBox.Show("配置文件丢失");                         return;                     }                       string query = "SET names gb2312;SELECT COUNT(id) FROM fx_user WHERE name='" + user + "' AND password=MD5('" + psd + "') AND userid='" + power + "'";                     MySqlConnection cn = new MySqlConnection("server=" + ipaddress + ";user id=" + mysqluser + ";Password=" + mysqlpsd + ";database=system;charset=gb2312");                                    cn.Open();                     MySqlCommand cm = new MySqlCommand(query, cn);                     MySqlDataReader read = cm.ExecuteReader();      //搜索满足 用户名，密码，操作员的记录。                     //如果记录没有-->密码或用户名错误                     if (read.Read())                                //如果记录多余1条-->数据错误，联系管理员                     {                                               //只有一条记录则成功登入                         int x = Int32.Parse(read[0].ToString());                         if (x == 0)                         {                             MessageBox.Show("用户名或密码错误");                         }                         else if (x > 1)                         {                             MessageBox.Show("用户冲突，请联系管理员");                         }                         else if (x == 1)                         {                             //  MessageBox.Show("登入成功");                             main mf = new main(power, ipaddress, mysqluser, mysqlpsd);   //将操作员 和 IP地址传入 主窗体                                mf.Show();                             this.Hide();                             cn.Close();                         }                     }                 }                 catch (MySql.Data.MySqlClient.MySqlException ex)                 {                     switch (ex.Number)                     {                         case 0:                             MessageBox.Show("数据库连接失败1");                             break;                         case 1045:                             MessageBox.Show("数据库密码或用户名错误");                             break;                         default:                             MessageBox.Show("数据库连接失败2");                             break;                     }                 }             }         }