c#mysql数据库

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 WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void button1_Click(object sender, EventArgs e)
        {
            MySqlConnection Conn = new MySqlConnection("Database=admin;server=localhost;User Id=root;Password=");
            
            string sql = "select * from user";
            MySqlCommand Da = new MySqlCommand(sql, Conn);
            Conn.Open();
            //MySqlDataAdapter ad = new MySqlDataAdapter();
            MySqlDataReader re = Da.ExecuteReader();
            //re.Read();
            //DataSet a = new DataSet();
            string username1 = this.username.Text.Trim();
            string password1 = this.password.Text.Trim();
            //string u1=re[1].ToString();
            //string p1=re[2].ToString();
            if (username1 == "" || password1 == "")
            {
                MessageBox.Show("用户名不能为空");

            }
            else {
                if (re.Read()) {

                    string u1 = re[1].ToString();
                    string p1=re[2].ToString();
                    if (username1 == u1 || password1 == p1)
                    {

                        MessageBox.Show("正确");
                    }
                    else {

                        MessageBox.Show("密码错误");
                    }
                    
                
                }
             
            }
             
        }
    }
}