Serialize List<T> containing List<T>

Question

I am trying to serialize a list that contains non-system types.

Below is my serialization code which is working fine on the top level. and returns a valid XmlDocument, but doesn't seem to contain anything in a inner list.

I've looked around the net - and around SO - but can't seem to find anything!

Any help much appreciated.

Code:

public static XmlDocument SerializeToXML<T>(List<T> list, string rootElement)
{
    XmlAttributeOverrides overrides = new XmlAttributeOverrides();
    XmlAttributes attr = new XmlAttributes();
    attr.XmlRoot = new XmlRootAttribute(rootElement);
    overrides.Add(typeof(List<T>), attr);

    XmlDocument xmlDoc = new XmlDocument();
    XPathNavigator nav = xmlDoc.CreateNavigator();
    using (XmlWriter writer = nav.AppendChild())
    {
        XmlSerializer ser = new XmlSerializer(typeof(List<T>), overrides);

        ser.Serialize(writer, list);
    }
    return xmlDoc;
}

Code used to test:

[TestFixture]
public class BaseTesting
{
    [Test]
    public void test()
    {
        List<ListTestClass> list = new List<ListTestClass>();

        for (int i = 0; i < 20; i++)
        {
            list.Add(new ListTestClass() { intProp = 1, stringProp = "string1", dtProp = DateTime.Now });
        }

        XmlDocument doc = Beyond.Base.Util.XMLUtils.SerializeToXML<ListTestClass>(list, "root");
    }
}

public class ListTestClass
{
    public int intProp { get; set; }

    public string stringProp { get; set; }

    public DateTime dtProp { get; set; }

    [XmlElement("Inner",typeof(InnerListTestClass))]
    public InnerListTestClass inner { get { return new InnerListTestClass() { intProp = 1, stringProp = "string1", dtProp = DateTime.Now }; } }
}

public class InnerListTestClass
{
    public int intProp { get; set; }

    public string stringProp { get; set; }

    public DateTime dtProp { get; set; }
}

XML Output:

<root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
  <ListTestClass>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T09:43:35.1017998+01:00</dtProp>
  </ListTestClass>
</root>

Answer 1

inner property must have setter in order to be serializable.

If you change it to

public InnerListTestClass inner { get; set; }

It will be serialized, as you expect it to.

<ListTestClass>
<intProp>1</intProp>
<stringProp>string1</stringProp>
<dtProp>2011-06-07T01:57:07.1200742-07:00</dtProp>
<Inner>
    <intProp>1</intProp>
    <stringProp>string1</stringProp>
    <dtProp>2011-06-07T01:57:07.1210743-07:00</dtProp>
</Inner>
</ListTestClass>