private void preencherDataGrid()
{
MercadoModel mer = new MercadoModel();
DataTable dt = new DataTable();
dt = mer.verAvalicoesClientes(Econobuy.Login.user_id);
dataGridView1.DataSource = dt;
if (dt.Rows.Count > 0)
{
dataGridView1.Columns["codigo"].Visible = false;
}
}