private void register(object sender, RoutedEventArgs e)
        {
            var todoItem = new TodoItem3
            {
                Name     = textBox.Text,
                Course   = comboBox.Items[comboBox.SelectedIndex].ToString(),
                username = textBox2.Text,
                password = passwordBox.Password,
                email    = textBox3.Text,
                phoneno  = textBox4.Text
            };
            var todoItem2 = new TodoItem4
            {
                username = textBox2.Text,
                password = passwordBox.Password,
                value    = "Faculty"
            };
            string pw1 = passwordBox.Password;
            string pw2 = passwordBox2.Password;

            if (pw1.Equals(pw2))
            {
                InsertTodoItem(todoItem);
                InsertTodoItem(todoItem2);
                this.Frame.Navigate(typeof(MainPage), null);
            }
            else
            {
            }
        }
        private async Task InsertTodoItem(TodoItem3 todoitem)
        {
            await registerstudent.InsertAsync(todoitem);

            items.Add(todoitem);
        }