private void InsertUser(string fullName, string userName, string password, string email)
        {
            Model.StdMarksRepo user = new Model.StdMarksRepo();
            user.AddUser(fullName, userName, password, email);
            Model.StudentRegistration check = user.ValidateUser(tbluname.Text, tblpassword.Text);

            if (check != null)
            {
                Session["userName"] = check.FullName;
                Session["userInfo"] = check;
                Response.Redirect("StudentViewHome.aspx");
            }
            else
            {
                Response.Redirect("Default.aspx");
            }
        }