private void deleteButton_Click(object sender, EventArgs e)
        {
            Hide();

            AddOrUpdateForm deleteForm = new AddOrUpdateForm(FormType.Delete);
            deleteForm.Show();
        }
        private void findButton_Click(object sender, EventArgs e)
        {
            Hide();

            AddOrUpdateForm findForm = new AddOrUpdateForm(FormType.Find);
            findForm.Show();
        }
        private void addButton_Click(object sender, EventArgs e)
        {
            Hide();

            AddOrUpdateForm addForm = new AddOrUpdateForm(FormType.Add);
            addForm.Show();
        }