Winform+Mysql登录

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; //引用mysql server命名空间
namespace pay
{
    public partial class login : Form
    {
        public static string ConnectionStr = "Server=127.0.0.1;Port=3306;Database=test;user=root;password=123456789;";//数据库信息
        public static  string name;
        public static  string password1;
        public static string role;
        public login()
        {
            InitializeComponent();
        }

        private void loginbutton_Click(object sender, EventArgs e)
        {
            name = username.Text.Trim();
            password1 = password.Text.Trim();
            role = this.comboBoxrole.SelectedItem.ToString();
            if (name == "" || password1 == "" || role == "")
            {
                MessageBox.Show("请将信息输入完整！","提示",MessageBoxButtons.OK);
            }
            else
            {
                MySqlConnection conn = new MySqlConnection(login.ConnectionStr);
                conn.Open();
                if (role=="管理员")
                {
                    String sql = "select EmpId,Password from Employee where ScheduleType='管理员' and EmpId='" + name + "'and Password='" + password1 + "'";//SQL语句实现表数据的读取
                    MySqlCommand cmd = new MySqlCommand(sql, conn);
                    MySqlDataReader sqlDataReader = cmd.ExecuteReader();
                    if (sqlDataReader.HasRows)  //如果能查到，说明该用户密码存在
                    {
                        MessageBox.Show("登陆成功");
                        this.Close();
                        conn.Close();
                    }
                    else
                    {
                        MessageBox.Show("账号或密码错误或未注册","提示",
                            MessageBoxButtons.OK,MessageBoxIcon.Warning);
                    }
                }
                else if (role=="钟点工")
                {
                    String sql = "select EmpId,Password from Employee where ScheduleType='钟点工' and EmpId='" + name + "'and Password='" + password1 + "'";//SQL语句实现表数据的读取
                    MySqlCommand cmd = new MySqlCommand(sql, conn);
                    MySqlDataReader sqlDataReader = cmd.ExecuteReader();
                    if (sqlDataReader.HasRows)  //如果能查到，说明该用户密码存在
                    {
                        MessageBox.Show("登陆成功");
                        this.Close();
                        conn.Close();
                    }
                    else
                    {
                        MessageBox.Show("账号或密码错误或未注册","提示",
                            MessageBoxButtons.OK,MessageBoxIcon.Warning);
                    }
                }
                else if (role=="销售员工")
                {
                    String sql = "select EmpId,Password from Employee where ScheduleType='销售员工' and EmpId='" + name + "'and Password='" + password1 + "'";//SQL语句实现表数据的读取
                    MySqlCommand cmd = new MySqlCommand(sql, conn);
                    MySqlDataReader sqlDataReader = cmd.ExecuteReader();
                    if (sqlDataReader.HasRows)  //如果能查到，说明该用户密码存在
                    {
                        MessageBox.Show("登陆成功");
                        this.Close();
                        conn.Close();
                    }
                    else
                    {
                        MessageBox.Show("账号或密码错误或未注册","提示",
                            MessageBoxButtons.OK,MessageBoxIcon.Warning);
                    }
                }
                else
                {
                    String sql = "select EmpId,Password from Employee where ScheduleType='普通职员' and EmpId='" + name + "'and Password='" + password1 + "'";//SQL语句实现表数据的读取
                    MySqlCommand cmd = new MySqlCommand(sql, conn);
                    MySqlDataReader sqlDataReader = cmd.ExecuteReader();
                    if (sqlDataReader.HasRows)  //如果能查到，说明该用户密码存在
                    {
                        MessageBox.Show("登陆成功");
                        this.Close();
                        conn.Close();
                    }
                    else
                    {
                        MessageBox.Show("账号或密码错误或未注册","提示",
                            MessageBoxButtons.OK,MessageBoxIcon.Warning);
                    }
                }

            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }
}