protected void btnYes_Click(object sender, EventArgs e)
        {
            if (Page.IsValid)
            {
                // Check is there a query string "classid" in the URL
                if (Request.QueryString["classId"] != null)
                {
                    // Create a Student object.
                    ClassStudent objStudent = new ClassStudent();
                    objStudent.ParentID = Convert.ToInt32(Session["LoginID"]);
                    objStudent.StudentName = txtStudentName.Text;
                    objStudent.TuitionClassID = Convert.ToInt32(lblTuitionClassID.Text);

                    int errorCode = objStudent .add();
                    if (errorCode == 0)
                    {
                        // Display appropriate message
                        lblMessage.Text = "Class registered successfully.";
                        // Disable "Yes" and "No" buttons,
                        btnYes.Enabled = false;
                        btnNo.Enabled = false;
                        //Display link back to the view staff page
                        lnkReturn.Visible = true;
                    }
                }
            }
        }
        protected void cuvDeleteClass_ServerValidate(object source, ServerValidateEventArgs args)
        {
            if (Page.IsValid)
            {
                ClassStudent objClassStudent = new ClassStudent();

                if (objClassStudent.studentNull(Convert.ToInt32(lblTuitionClassID.Text)) == false)
                {
                    args.IsValid = false;
                    btnYes.Enabled = false;
                    btnNo.Enabled = false;
                    lnkViewClassSchedule.Visible = true;
                }
                else
                {
                    args.IsValid = true;
                }
            }
        }