Deserializing XML with DataContractSerializer

Question

I have a web service that returns the following data:

<?xml version=""1.0"" encoding=""UTF-8""?>
<RESPONSE>
    <KEY>12345</KEY>
    <PROPERTY>
        <PROPERTY_ADDRESS>
            <STREET_NUM>25</STREET_NUM>
            <STREET_ADDRESS>ELM ST</STREET_ADDRESS>
            <STREET_PREFIX/>
            <STREET_NAME>ELM</STREET_NAME>
            <STREET_TYPE>ST</STREET_TYPE>
            <STREET_SUFFIX/>
        </PROPERTY_ADDRESS>
    </PROPERTY>
</RESPONSE>

I have a class structure to match:

[DataContract(Name="RESPONSE", Namespace="")]
public class Response
{
    [DataMember(Name="KEY")]
    public string Key { get; set; }

    [DataMember(Name = "PROPERTY")]
    public Property Property { get; set; }
}

[DataContract(Name="PROPERTY", Namespace="")]
public class Property
{
    [DataMember(Name="PROPERTY_ADDRESS")]
    public PropertyAddress Address { get; set; }
}


[DataContract(Name="PROPERTY_ADDRESS", Namespace="")]
public class PropertyAddress
{
    [DataMember(Name="STREET_NUM")]
    public string StreetNumber { get; set; }

    [DataMember(Name = "STREET_ADDRESS")]
    public string StreetAddress { get; set; }

    [DataMember(Name = "STREET_PREFIX")]
    public string StreetPrefix { get; set; }

    [DataMember(Name = "STREET_NAME")]
    public string StreetName { get; set; }

    [DataMember(Name = "STREET_TYPE")]
    public string StreetType { get; set; }

    [DataMember(Name = "STREET_SUFFIX")]
    public string StreetSuffix { get; set; }
}

My deserialization code looks like this:

[Test]
public void TestMapping()
{
    var serializer = new DataContractSerializer(typeof(Response));

    Response response = null;

    using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(XmlData)))
    {
        response = (Response)serializer.ReadObject(ms);
    }

    //This works
    Assert.AreEqual("12345", response.Key);

    //This works
    Assert.AreEqual("25", response.Property.Address.StreetNumber);

    //This FAILS. StreetAddress is null
    Assert.AreEqual("ELM ST", response.Property.Address.StreetAddress);
}

For the life of me I can't figure out why StreetAddress is failing. It's got to be something simple that I'm missing.

Solution 1

DataContractSerializer expects things to be in alphabetical order. You need to add Order to your Data Members for this to work correctly.

[DataContract(Name = "PROPERTY_ADDRESS", Namespace = "")]
public class PropertyAddress
{
    [DataMember(Name = "STREET_NUM", Order=0)]
    public string StreetNumber { get; set; }

    [DataMember(Name = "STREET_ADDRESS", Order=1)]
    public string StreetAddress { get; set; }

    [DataMember(Name = "STREET_PREFIX", Order=2)]
    public string StreetPrefix { get; set; }

    [DataMember(Name = "STREET_NAME", Order=3)]
    public string StreetName { get; set; }

    [DataMember(Name = "STREET_TYPE", Order=4)]
    public string StreetType { get; set; }

    [DataMember(Name = "STREET_SUFFIX",Order=5)]
    public string StreetSuffix { get; set; }
}

Solution 2

You have to augment your data contract with the order of the elements because DataContractSerializer expects the elements to be sorted alphabetically by default. Which is not the case with your XML.

Here's the code:

[DataContract(Name = "PROPERTY_ADDRESS", Namespace = "")]
public class PropertyAddress
{
    [DataMember(Name = "STREET_NUM", Order=1)]
    public string StreetNumber { get; set; }

    [DataMember(Name = "STREET_ADDRESS", Order=2)]
    public string StreetAddress { get; set; }

    [DataMember(Name = "STREET_PREFIX", Order=3)]
    public string StreetPrefix { get; set; }

    [DataMember(Name = "STREET_NAME", Order=4)]
    public string StreetName { get; set; }

    [DataMember(Name = "STREET_TYPE", Order=5)]
    public string StreetType { get; set; }

    [DataMember(Name = "STREET_SUFFIX", Order=6)]
    public string StreetSuffix { get; set; }
}