public void DataBindListDouble(string courseID)
{
lblCourseName.Text = bm.ReturnCourseName(courseID);
GridView1.DataSource = bm.HaveCourseStudentListBind(courseID);
GridView1.DataBind();
GridView2.DataSource = bm.HaveNoCourseStudentListBind(courseID, Request.Cookies["TeacherID"].Value.ToString());
GridView2.DataBind();
}