private void btnSua_Click(object sender, EventArgs e)
        {
            var frm = new frmAEContact(dgvContacts, "Sửa Dữ Liệu", dgvContacts.CurrentCell.RowIndex);

            frm.ShowDialog();
        }
        private void btnThem_Click(object sender, EventArgs e)
        {
            var frm = new frmAEContact(dgvContacts, "Thêm Dữ Liệu");

            frm.ShowDialog();
        }