Deserialize XML Rest WebApi Call?

Question

I have been following some online examples and for some reason I cannot successfully deserialize the following XML document:

<?xml version="1.0" encoding="UTF-8"?>
<result>
    <postcode>BD1 1LT</postcode>
    <geo>
        <lat>53.793063240118215</lat>
        <lng>-1.7540318423563699</lng>
        <easting>416300.0</easting>
        <northing>433000.0</northing>
        <geohash>http://geohash.org/gcwf00dz21g1</geohash>
    </geo>
    <administrative>
        <council>
            <title>Bradford</title>
            <uri>http://statistics.data.gov.uk/id/statistical-geography/E08000032</uri>
            <code>E08000032</code>
        </council>
        <ward>
            <title>City</title>
            <uri>http://statistics.data.gov.uk/id/statistical-geography/E05001347</uri>
            <code>E05001347</code>
        </ward>
        <constituency>
            <title>Bradford West</title>
            <uri>http://statistics.data.gov.uk/id/statistical-geography/E14000589</uri>
            <code>E14000589</code>
        </constituency>
    </administrative>
</result>

I've tried all sorts of combinations:

[DataContract(Name = "result", Namespace = "")]
public class Result
{
    [DataMember(Name = "postcode")]
    public string Postcode { get; set; }
    [DataMember(Name = "geo")]
    public Geo Geo { get; set; } 
}

[DataContract(Name = "geo")]
public class Geo
{
    [DataMember(Name = "lat")]
    public string Lat { get; set; } 
}

But all I can get is the post code and nothing else. Above is what I have working atm.

Below is what I have put together following some examples:

    [Test]
    public void TestRestCall()
    {
        var url = "http://uk-postcodes.com/postcode/";
        var urlParameters = "bd11lt.xml";
        var client = new HttpClient();
        client.BaseAddress = new Uri(url);

        // Add an Accept header for JSON format.
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/xml"));

        // List data response.
        HttpResponseMessage response = client.GetAsync(urlParameters).Result;  // Blocking call!
        if (response.IsSuccessStatusCode)
        {
            // Parse the response body. Blocking!
            var dataObjects = response.Content.ReadAsAsync<Result>().Result;
            //Console.WriteLine("{0}", dataObjects.Geo.);
        }
        else
        {
            Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
        } 
    }

UPDATE:

The Geo property is null and that's as far as I can get with this.

Answer 1

There are two problems that I see. One is with the ordering and another is with namespace.

You need to specify the order on all of your properties and objects but you also need to specify the namespace on all of them.

    [DataContract(Name = "result", Namespace = "")]
    public class Result
    {
        [DataMember(Name = "postcode", Order = 1)]
        public string Postcode { get; set; }

        [DataMember(Name = "geo", Order = 2)]
        public Geo Geo { get; set; }
    }

Likewise on your GEO object you have to specify both for the mapping to work on the HttpClient.

    [DataContract(Name = "geo", Namespace = "")]
    public class Geo
    {
        [DataMember(Name = "lat", Order = 1)]
        public string Lat { get; set; }
    }

Hope that helps.

Answer 2

This is an ordering thing, but it's one you can work around with your definition of Result. DataContractSerializer, unless told otherwise, expects elements to be in alphabetical order, not the order defined in the class. But, you can use the Order property of DataMember to explicitly tell it in what order to expect and emit elements.

Changing your definition of Result to

[DataContract(Name = "result", Namespace = "")]
public class Result
{
    [DataMember(Name = "postcode", Order = 1)]
    public string Postcode { get; set; }

    [DataMember(Name = "geo", Order = 2)]
    public Geo Geo { get; set; }
}

should fix your issue. You can refer to MSDN for a more complete description of ordering semantics in data contracts.

As per @LouieBacaj's answer, you will also need to add the empty namespace to your Geo class to correctly deserialze the nested element:

[DataContract(Name = "geo", Namespace = "")]
public class Geo
{
    [DataMember(Name = "lat")]
    public string Lat { get; set; }
}

Answer 3

public string Geo is supposed to be public Geo Geo, isn't it?