XML : Cannot write XML to file

I writing Android app on C# (Xamarin)

I trying to write xml to file

Code of creating XML

  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");              Console.WriteLine(doc.OuterXml);    

I try to write it like this, but I don't see it on device.

      var documentsPath = Environment.GetFolderPath(Environment.SpecialFolder.Personal);  var filePath = Path.Combine(documentsPath, "myFile.xml");  File.WriteAllText(filePath, doc.ToString());    

How write it to file or maybe something isn't wright in my code?