登录界面： 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.SqlClient; namespace _123 { public partial class login : Form { public login() { InitializeComponent(); } private void quxaio_Click(object sender, EventArgs e) { MessageBox.Show("确定退出吗？"); this.Close(); } private void denglu_Click(object sender, EventArgs e) { if (this.zhanghao.Text.Trim() == ""|this.mima.Text.Trim()=="") { if(this.zhanghao.Text.Trim()=="") { MessageBox.Show("帐号不能为空！请从洙新输入！"); } else if (this.mima.Text.Trim() == "") { MessageBox.Show("密码不能为空！请从新输入！"); } } else { string ConnStr = @"server=.;database=user_db;uid=sa;pwd=zhangrui;"; SqlConnection conn = new SqlConnection(ConnStr); conn.Open(); 本文来源：https://www.wddqw.com/doc/c017ee8ba0116c175f0e48d6.html