private void Modificar()
        {
            frmEmpresaMant frm = new frmEmpresaMant(Convert.ToInt64(grdDatos.SelectedCells[0].Value.ToString()));

            frm.ShowDialog(this);
            Listar_Cliente();
        }
        private void btn_Agregar_Click(object sender, EventArgs e)
        {
            Cursor = Cursors.WaitCursor;

            frmEmpresaMant frm = new frmEmpresaMant(0);

            frm.ShowDialog(this);
            Listar_Cliente();

            Cursor = Cursors.Default;
        }