protected void btn_attend_Click(object sender, EventArgs e)
    {
        tbl_attend att = new tbl_attend();

        att.attend_curr_date  = Calendar1.SelectedDate.ToString();
        att.attend_class      = DropDownList1.SelectedValue;
        att.attend_attendance = RadioButtonList1.SelectedValue;
        db.tbl_attends.InsertOnSubmit(att);

        db.SubmitChanges();

        Response.Write("<script>alert('You are Present') </script>");
    }
 partial void Deletetbl_attend(tbl_attend instance);
 partial void Updatetbl_attend(tbl_attend instance);
 partial void Inserttbl_attend(tbl_attend instance);