public static Exam ex = new Exam(); //声明静态全局变量 考试窗口实例 private void LogButt_Click(object sender, EventArgs e) { //判断是否选择登陆身份 if (useIdeTextBox.Text == "") { MessageBox.Show("请选择登陆身份!"); } else { //判断是否输入用户名和密码 if (accTextBox.Text == "" || pwdTxtBox.Text == "") { MessageBox.Show("请输入用户名和密码!"); } else { //如果是考生 if (useIdeTextBox.Text == "考生") { //判断用户名密码是否符合 OleDbConnection con = DataClass.DBCon(); con.Open(); OleDbCommand com = new OleDbCommand( "select * from UserInfo where userAcc='" + accTextBox.Text + "' and userPwd='" + pwdTxtBox.Text + "' and userIde=0", con); OleDbDataReader red = com.ExecuteReader(); red.Read(); if (red.HasRows) { ComVal.userPwd = pwdTxtBox.Text; ComVal.userAcc = accTextBox.Text; Exam._Useracc = ComVal.userAcc; //传递用户名 ex.Show(); //显示考试窗口 this.Hide(); } else { MessageBox.Show("用户名或密码错误!"); } con.Close(); } else { //如果不是学生,则判断管理员的身份是否符合 OleDbConnection con = DataClass.DBCon(); con.Open(); OleDbCommand com = new OleDbCommand( "select * from UserInfo where userIde=1 and userAcc='" + accTextBox.Text + "' and userPwd='" + pwdTxtBox.Text + "'", con); OleDbDataReader red = com.ExecuteReader(); red.Read(); if (red.HasRows) { //上传用户名密码 ComVal.userPwd = pwdTxtBox.Text; ComVal.userAcc = accTextBox.Text; ComVal.userName = red[2].ToString(); ad.Show();//显示管理员窗口 this.Hide(); } else { MessageBox.Show("用户名或密码错误!"); } con.Close(); } } } }