private void getStudents2()
{
metroTextBox1.ResetText();
var db = new dc_student_managementDataContext();
var results = from c in db.Student
where c.StuNo.Equals(metroTextBox2.Text)
select c;
if (results.Count() == 0)
{
metroTextBox1.Text = "查询结果为空，请重新输入学号";
}
foreach (var r in results)
{
metroTextBox1.Text = "姓名：" + r.StuName + " 学号：" + r.ClassNo + " 班级" + r.ClassNo + " 性别：" + r.Sex + " 生日" + r.BirthDay + "\r\n";
}
}
private void getStudents3()
{
metroTextBox1.ResetText();
var db = new dc_student_managementDataContext();
var results = from c in db.StuCou
join s in db.Course
on c.CouNo equals s.CouNo
where c.StuNo.Equals(metroTextBox2.Text)
select new { c.CouNo, s.CouName, c.Grade };
if (results.Count() == 0)
{
metroTextBox1.Text = "查询结果为空，请重新输入学号";
}
/*if (frmLogin.ID != metroTextBox2.Text)
* {
* metroTextBox1.Text += frmLogin.ID;
* metroTextBox1.Text += "\r\n";
* metroTextBox1.Text += metroTextBox2.Text;
* metroTextBox1.Text += "你不能查询其他学生的成绩，请输入你自己的学号";
* }*///想实现一个学生只能查询自己的成绩
float?avg = 0;
int count = 0;
foreach (var r in results)
{
count++;
avg += r.Grade;
metroTextBox1.Text += "课程号：" + r.CouNo + " 课程名：" + r.CouName + " 成绩：" + r.Grade + "\r\n";
}
avg /= count;
metroTextBox1.Text += "平均成绩：" + avg.ToString();
}
