I need to put an ID in the print file using C# and Itextsharp

Question

Edit: if anyone has the same problem as me, I solved by playing the " Pdfptable ID = new Pdfptable(1)" out to be a global var and put the "pdfdoc.add(ID)" part out of the while

So, for my work, I need to print a report, and I want to do a report identification, in the SQL database has already been created, but as I will add it to the code to print?

As an attempt, I used this code:

try
{
    con.Open();
    SqlDataReader registro = cmd.ExecuteReader();
    while (registro.Read())
    {
        string id = registro["ID"].ToString();
        PdfPTable ID = new PdfPTable(7);
        ID.AddCell(registro["ID"].ToString());
        pdfdoc.Add(ID);
    }
    con.Close()
}
catch
{
  throw;
}