Writing many variables into textfile

I've this piece of code:

using (StreamWriter writer = new StreamWriter("C:\\Users\\HP8200\\Desktop\\teste.txt"))
{            
    string numcont = _transaction.PartyFederalTaxID;

    double numenc = _transaction.BillToPartyID;
    double numfatura = _transaction.BillToPartyID;
    string zona = _transaction.BillToPartyCountryID;
    DateTime data = _transaction.CreateDate;
    string ean = _transaction.ATDocCodeId;
    double iva = _transaction.TotalTaxAmount;
    double precoantesdisc = _transaction.TotalLineItemDiscountAmount;
    double preconet = _transaction.TotalNetAmount;

    writer.WriteLine(numcont,";", numenc,";", numfatura,";", data,";", zona, Environment.NewLine , 
        ean,";", iva,";", precoantesdisc,";", preconet);
}

MessageBox.Show("gravou");

And it should save all those variables into the textfile I say but it only writes the first variable(numcont). What I need to do so it writes all the variables I need on that textfile? Feel free to ask for more code.