c# - Serialize Property as Xml Attribute in Element

Question

I have the following class:

[Serializable]
public class SomeModel
{
    [XmlElement("SomeStringElementName")]
    public string SomeString { get; set; }

    [XmlElement("SomeInfoElementName")]
    public int SomeInfo { get; set; }
}

Which (when populated with some test data) and Serialized using XmlSerializer.Serialize() results in the following XML:

<SomeModel>
  <SomeStringElementName>testData</SomeStringElementName>
  <SomeInfoElementName>5</SomeInfoElementName>
</SomeModel>

What I need to have is:

<SomeModel>
  <SomeStringElementName Value="testData" />
  <SomeInfoElementName Value="5" />
</SomeModel>

Is there a way to specify this as attributes without writing my own custom serialization code?

Answer 1

You will need wrapper classes:

public class SomeIntInfo
{
    [XmlAttribute]
    public int Value { get; set; }
}

public class SomeStringInfo
{
    [XmlAttribute]
    public string Value { get; set; }
}

public class SomeModel
{
    [XmlElement("SomeStringElementName")]
    public SomeStringInfo SomeString { get; set; }

    [XmlElement("SomeInfoElementName")]
    public SomeIntInfo SomeInfo { get; set; }
}

or a more generic approach if you prefer:

public class SomeInfo<T>
{
    [XmlAttribute]
    public T Value { get; set; }
}

public class SomeModel
{
    [XmlElement("SomeStringElementName")]
    public SomeInfo<string> SomeString { get; set; }

    [XmlElement("SomeInfoElementName")]
    public SomeInfo<int> SomeInfo { get; set; }
}

And then:

class Program
{
    static void Main()
    {
        var model = new SomeModel
        {
            SomeString = new SomeInfo<string> { Value = "testData" },
            SomeInfo = new SomeInfo<int> { Value = 5 }
        };
        var serializer = new XmlSerializer(model.GetType());
        serializer.Serialize(Console.Out, model);
    }
}

will produce:

<?xml version="1.0" encoding="ibm850"?>
<SomeModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <SomeStringElementName Value="testData" />
  <SomeInfoElementName Value="5" />
</SomeModel>