protected void GridViewStudents_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            ClassStudents loadDetails = new ClassStudents();

            loadDetails.LoadStudentDetailsToStudentGrade(GridViewStudents);
            GridViewStudents.PageIndex = e.NewPageIndex;
            GridViewStudents.DataBind();
        }
 protected void Page_Load(object sender, EventArgs e)
 {
     if (!Page.IsPostBack)
     {
         ClassStudents loadDetails = new ClassStudents();
         loadDetails.LoadStudentDetailsToStudentGrade(GridViewStudents);
     }
 }