private void txttipofacc_TextChanged(object sender, EventArgs e)
        {
            if (txttipofacc.Text != "")
            {
                dgv.DataSource = sql.BuscaRegistro3(txttipofacc.Text);
            }

            else
            {
                dgv.DataSource = sql.MuestraRegsitros();
            }
        }