学生成绩管理系统代码c#+sql.docVIP

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Data.SqlClient; namespace 学生成绩管理系统 { public partial class Login : Form { static public string sn,sub; public Login() { InitializeComponent(); } Form2 fr2 = new Form2(); Form3 fr3 = new Form3(); Form4 fr4 = new Form4();//——————————————————————————创建新窗体 private void Login_Load(object sender, EventArgs e) { timer1.Start(); // ——————————————————————————Timer控件 } private void btnlogin_Click(object sender, EventArgs e) {//Data Source=LEE-PC;Initial Catalog=学生成绩管理系统;User ID=sa;Password=sa // string str = Data Source=LEE-PC;Initial Catalog=学生成绩管理系统;User ID=sa;Password=sa; string str = Data Source=LEE-PC;Initial Catalog=学生成绩管理系统;User ID=sa;Password=sa; SqlConnection conn = new SqlConnection(str);//———————————————————————————————————连接数据库 conn.Open(); if( txtname .Text==||txtpassword .Text==) MessageBox.Show (请不要遗漏信息！); if (rbtnmanager.Checked) { string cstr=select * from 用户登录 where 类别=管理员and 用户名=+txtname.Text.Trim ()+and 密码=+txtpassword .Text.Trim ()+; SqlCommand comm=new SqlCommand (cstr,conn ); SqlDataReader dr=comm.ExecuteReader (); if (dr.Read()) { sn = txtname.Text.Trim(); fr4.Show(); this.Visible = false; } else { MessageBox.Show(输入有误，请重新输入！); txtname.Text = ; txtpassword.Text = ; } } if (rbtnteacher.Checked) { string cstr = select * from 用户登录 where 类别=教师and 用户名= + txtname.Text.Trim() + and 密码= + txtpassword