Adding a new field to a class to be serialized

Question

To be able to serialize and deserialize a XML I had designed like this:

<?xml version="1.0" encoding="utf-8"?>
<DbConnections xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <DbConnectionInfo>
    <ServerName>SQLServer2k8</ServerName>
  </DbConnectionInfo>
  <DbConnectionInfo>
    <ServerName>SQLServer2k8R2</ServerName>
  </DbConnectionInfo>
</DbConnections>

I had written two classes like this below:

public class DbConnectionInfo
{
    public string ServerName { get; set; }
}

and

[Serializable]
[XmlRoot("DbConnections")]
public class DbConnections: List<DbConnectionInfo>
{
  //...
}

Now I want to expand my XML form and add one more field like this but is there is a way to design my class in a way that I don' have to REPEAT it in every XML tag? like this:

<?xml version="1.0" encoding="utf-8"?>
<DbConnections xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <DbConnectionInfo>
    <ServerName>SQLServer2k8</ServerName>
  </DbConnectionInfo>
  <DbConnectionInfo>
    <ServerName>SQLServer2k8R2</ServerName>
  </DbConnectionInfo>

   <UseWindowsAuthentication>Yes</UseWindowsAuthentication>
</DbConnections>

So I just really added that one line to previous XML: But my question is how should I modify my classes to add this? And is it even possible or a correct design?

<UseWindowsAuthentication>Yes</UseWindowsAuthentication>

Answer 1

Maybe something like this

[Serializable]
[XmlRoot("DbConnections")]
public class DbConnections
{
   List<DbConnectionInfo> DbConnectionInfos;
   Boolean UseWindowsAuthentication;
}

Edited to add: if you do not want nested elements, decorate your class as so

public class DbConnections
{
    [XmlElement("DbConnectionInfo")]
    public List<DbConnectionInfo> DbConnectionInfos;
    public Boolean UseWindowsAuthentication;
}

I tested this and the following xml was serialized

XmlSerializer serializer = new XmlSerializer(typeof(DbConnections));
            string xml;
            using (StringWriter textWriter = new StringWriter())
            {
                serializer.Serialize(textWriter, oDbConnections);
                xml = textWriter.ToString();
            }

<?xml version="1.0" encoding="utf-16"?>
<DbConnections xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <DbConnectionInfo>
    <ServerName>test</ServerName>
  </DbConnectionInfo>
  <DbConnectionInfo>
    <ServerName>test 2</ServerName>
  </DbConnectionInfo>
  <UseWindowsAuthentication>true</UseWindowsAuthentication>
</DbConnections>

Here is a link to more info on decorating for xml serialization