CollectionDataContract serialization not adding custom properties (DataMember)

Question

We have a legacy system that needs to be fed (XML) data in a most unstructured format. Is the following even possible with the .NET DataContractSerializer?

Given the following DataContracts

[CollectionDataContract(Name = "Options", ItemName = "Option")]
public class OptionItemCollection : List<OptionItem>
{
    [DataMember(Name = "Name")]
    public string Name { get; set; }

    public OptionItemCollection()
    {
    }

    public OptionItemCollection(IEnumerable<OptionItem> items) : base(items)
    {
    }
}

[DataContract(Name = "Option")]
public class OptionItem
{
    [DataMember]
    public string Text { get; set; }
    [DataMember]
    public string Value { get; set; }

}

Is it possible to serialize this collection directly into the following XML representation:

<Options>
    <Name>Juices</Name>
    <Option Value="1">Orange Juice</Option>
    <Option Value="2">Pineapple</Option>
    <Option Value="3">Fruit Punch</Option>
</Options>

NOTE: This is exactly how the legacy system expects the data to be submitted.

Or Even:

<Options>
    <Name>Juices</Name>
    <Option><Value>1</Value><Text>Orange Juice</Text></Option>
    <Option><Value>2</Value><Text>Pineapple</Text></Option>
    <Option><Value>3</Value><Text>Fruit Punch</Text></Option>
</Options>

Also NOTE that the emphasis is on the Name and Option element residing within the Options element.

Are you allowed to change the DataContracts? Are you allowed to use XML Serialization instead of DataContract Serialization? — mellamokb, Sep 21 '11 at 14:45
Yes we can. But I just wanted to know if it was possible with the [newer and more advanced] DataContractSerializer — Tawani, Sep 22 '11 at 13:14

score 4 · Answer 1 · answered Sep 21 '11 at 15:36

Yes. Although the DataContractSerializer doesn't explicitly support XML attributes, you can hand-roll it. Try this:

[CollectionDataContract(Name = "Options", ItemName = "Option")]
public class OptionItemCollection : List<OptionItem>
{
    [DataMember(Name = "Name")]
    public string Name { get; set; }

    public OptionItemCollection()
    {
    }

    public OptionItemCollection(IEnumerable<OptionItem> items)
        : base(items)
    {
    }
}

// note, remove attributes
public class OptionItem : IXmlSerializable
{
    public string Text { get; set; }

    public string Value { get; set; }

    public void WriteXml(XmlWriter writer)
    {
        writer.WriteAttributeString("Value", Value);
        writer.WriteElementString("Text", Text);
    }

    public void ReadXml(XmlReader reader)
    {
        // implement if necessary
        throw new NotImplementedException();
    }

    public System.Xml.Schema.XmlSchema GetSchema()
    {
        throw new NotImplementedException();
    }
}

score 4 · Answer 2 · answered Sep 30 '11 at 03:59

No, this is not possible with the DataContractSerializer (DCS). The DCS doesn't allow unwrapped collection elements. So you cannot have this:

<a>
  <b/>
  <b/>
  <b/>
  <c/>
</a>

But you can have this:

<a>
  <bb>
    <b/>
    <b/>
    <b/>
  </bb>
  <c/>
</a>

In your scenario you'll need to use the XmlSerializer.

CollectionDataContract serialization not adding custom properties (DataMember)

2 Answers2

Linked