private void button1_Click(object sender, EventArgs e)
        {
            FrmEmpleado c = new FrmEmpleado(null);

            c.ShowDialog();

            refreshDataGrid();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            int?id = getId();

            if (id != null)
            {
                FrmEmpleado c = new FrmEmpleado(id);
                c.ShowDialog();

                refreshDataGrid();
            }
        }