continue writing on same XML file without deleting in c#

Question

I have done this code so far works well, but the only issue is that the XML file gets deleted every time I use the method addUser, I want the code to continue writing under it

the code I wrote in c#:

 public static void AddUser(PersonData pd)
        {
            XmlTextWriter xWriter = new XmlTextWriter("D:\\PersonData.Xml", Encoding.UTF8);
            xWriter.Formatting = Formatting.Indented;
            xWriter.WriteStartElement("User");
            xWriter.WriteAttributeString("idNumber", pd.IdNumber1);

            xWriter.WriteStartElement("Firstname");
            xWriter.WriteString(pd.FirstName1);
            xWriter.WriteEndElement();//<FirstName>

            xWriter.WriteStartElement("LastName");
            xWriter.WriteString(pd.LastName1);
            xWriter.WriteEndElement();//<LastName>

            xWriter.WriteStartElement("DateOfBirth");
            xWriter.WriteString(pd.DateOfBirth1.ToString());
            xWriter.WriteEndElement();//<DateOfBirth>

            xWriter.WriteStartElement("Address");
            xWriter.WriteString(pd.Address1);
            xWriter.WriteEndElement();//<Address>

            xWriter.WriteEndElement();//<user>
            xWriter.Close();
        }

the XML output:

<User idNumber="316447077">
  <Firstname>majd</Firstname>
  <LastName>sadi</LastName>
  <DateOfBirth>29/03/1998 14:54:50</DateOfBirth>
  <Address>hohos</Address>
</User>

the XML output that I want to do:

 <User idNumber="316447077">
      <Firstname>majd</Firstname>
      <LastName>sadi</LastName>
      <DateOfBirth>29/03/1998 14:54:50</DateOfBirth>
      <Address>hohos</Address>
    </User>
    <User idNumber="316447077">
      <Firstname>majd</Firstname>
      <LastName>sadi</LastName>
      <DateOfBirth>29/03/1998 14:54:50</DateOfBirth>
      <Address>hohos</Address>
    </User>

Answer 1

Assuming you have a root node to your XML (not valid XML without it), you could do this with XElement:

XElement xe;

if (File.Exists("D:\\PersonData.Xml"))
  xe = XElement.Load("D:\\PersonData.Xml");
else
  xe = new XElement("Users");

XElement newUser = new XElement("User");
newUser.Add(new XAttribute("idNumber", pd.IdNumber1));
newUser.Add(new XElement("Firstname", pd.FirstName1));
newUser.Add(new XElement("LastName", pd.LastName1));
newUser.Add(new XElement("DateOfBirth", pd.DateOfBirth1.ToString()));
newUser.Add(new XElement("Address", pd.Address1));

xe.Add(newUser);
xe.Save("D:\\PersonData.Xml");

Answer 2

try to flush like xWriter.Flush() after you write your end element?