XML : Add string to xml file

I writing Android app on Xamarin (C#)

I have xml file.

  <Order CallConfirm="1"         PayMethod="Безнал"         QtyPerson=""         Type="2"         PayStateID="0"         Remark="{Comment}"         RemarkMoney="0"         TimePlan=""         Brand="1"         DiscountPercent="0"         BonusAmount="0"         Department="">      <Customer Login=""                FIO="{FIO}" />      <Address CityName="{CityName}"               StationName=""               StreetName="{StreetName}"               House="{HouseName}"               Corpus=""               Building=""               Flat="{FlatName}"               Porch=""               Floor=""               DoorCode="" />      <Phone Code="{Code}"             Number="{Phone}" />      <Products>          <Product Code="{ProductCode}"                   Qty="{QTY}" />      </Products>  </Order>    

I have list of products

I already have Code="{ProductCode}" Qty="{QTY}" string. But I want to add same string with product attributes when I tap button.

How I can realize this?

I realized writing xml to file

  XmlDocument doc = new XmlDocument();          XmlElement el = (XmlElement)doc.AppendChild(doc.CreateElement("Order"));          el.SetAttribute("CallConfirm", "1");          el.SetAttribute("PayMethod", "Безнал");          el.SetAttribute("QtyPerson", "");          el.SetAttribute("Type", "2");          el.SetAttribute("PayStateID", "0");          el.SetAttribute("Remark", "{Comment}");          el.SetAttribute("RemarkMoney", "0");          el.SetAttribute("TimePlan", "");          el.SetAttribute("Brand", "1");          el.SetAttribute("DiscountPercent", "0");          el.SetAttribute("BonusAmount", "0");          el.SetAttribute("Department", "");            XmlElement el2 = (XmlElement)el.AppendChild(doc.CreateElement("Customer"));            el2.SetAttribute("Login", "");          el2.SetAttribute("FIO", "{FIO}");            XmlElement el3 = (XmlElement)el.AppendChild(doc.CreateElement("Address"));            el3.SetAttribute("CityName", "{CityName}");          el3.SetAttribute("StationName", "");          el3.SetAttribute("StreetName", "{StreetName}");          el3.SetAttribute("House", "{HouseName}");          el3.SetAttribute("Corpus", "");          el3.SetAttribute("Building", "");          el3.SetAttribute("Flat", "{FlatName}");          el3.SetAttribute("Porch", "");          el3.SetAttribute("Floor", "");          el3.SetAttribute("DoorCode", "");            XmlElement el4 = (XmlElement)el.AppendChild(doc.CreateElement("Phone"));            el4.SetAttribute("Code", "{Code}");          el4.SetAttribute("Number", "{Phone}");            XmlElement el5 = (XmlElement)el.AppendChild(doc.CreateElement("Products"));          XmlElement el6 = (XmlElement)el5.AppendChild(doc.CreateElement("Product"));            el6.SetAttribute("Code", "{ProductCode}");          el6.SetAttribute("Qty", "{QTY}");              Console.WriteLine ("TUT");          var documentsPath = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal);          var filePath = Path.Combine(documentsPath, "myFile.xml");          //File.WriteAllText(filePath, doc.OuterXml);          doc.Save (filePath);          Console.WriteLine(doc.OuterXml);