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  • 简易教程C#和MySql数据库完成登陆用户名登陆飞来飞去

    1.数据库建立如下:

    2.操作流程如下:

    (1)开始状态,数据库未连接

    (2)链接数据库

    (3)输入用户名和密码

    (4)登陆成功

    程序如下:

    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 MySql.Data.MySqlClient;

    namespace MysqlTest1
    {
        public partial class Form1 : Form
        {
            MySqlConnection conn = null;//在类里面定义变量
            public Form1()
            {
                InitializeComponent();
                                        //在构造函数里面初始化
                conn = new MySqlConnection("Data Source=localhost;Initial Catalog=test;User ID=root;Password=mysql;");
                                        //在方法里面使用
            }

            private void btnLink_Click(object sender, EventArgs e)
            {
                conn.Open();        //打开对象
                if (conn.State.ToString() == "Open")
                {
                    lab_state.Text  = "数据库连接成功!";
                }
                else
                {
                    lab_state.Text = "数据库连接失败!";
                }

            }

            private void button1_Click(object sender, EventArgs e)
            {
                conn.Close();
                if(conn.State.ToString()=="Closed")
                {
                    lab_state.Text = "数据库已关闭!";
                }
            }

            private void btn_load_Click(object sender, EventArgs e)
            {
                string userName=txt_User.Text.Trim();       //获取用户名
                string password = txt_Password.Text.Trim(); //获取密码
                string CmdStr = "Select * from test.user where name='"+userName+"' AND password='"+password+"'";
                MySqlCommand cmd = new MySqlCommand(CmdStr,conn);   //定义查询语句
               
                MySqlDataReader sreader = cmd.ExecuteReader();      //执行查询操作
                if (sreader.Read())
                {
                    MessageBox.Show("登录成功!");
                }
                else
                {
                    MessageBox.Show("登录失败!");
                }
                sreader.Close();        //每次执行完毕都得关闭reader
            }  
        }
    }

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  • 原文地址:https://www.cnblogs.com/jife/p/3016905.html
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