How to use a DataContract for the first element in a nested json array?

Question

The objective is to instruct the serializer using DataContract to store the first element only, allowing me to eliminate the use of IList<MyObject>

Sample JSON

{
    "registrant_contacts": [
        {
            "id": null,
            "type": 1,
            "name": "Dns Admin",
            "organization": "Google Inc.",
            "address": "Please contact [email protected], 1600 Amphitheatre Parkway",
            "city": "Mountain View",
            "zip": "94043",
            "state": "CA",
            "country": null,
            "country_code": "US",
            "phone": "+1.6502530000",
            "fax": "+1.6506188571",
            "email": "[email protected]",
            "url": null,
            "created_on": null,
            "updated_on": null
        }
    ]
}

Sample DataContract

[DataContract]
public class RegistrantContact
{

    [DataMember(Name="id")]
    public object id { get; set; }

    [DataMember(Name="type")]
    public int type { get; set; }

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

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

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

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

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

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

    [DataMember(Name="country")]
    public object country { get; set; }

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

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

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

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

    [DataMember(Name="url")]
    public object url { get; set; }

    [DataMember(Name="created_on")]
    public object created_on { get; set; }

    [DataMember(Name="updated_on")]
    public object updated_on { get; set; }
}

[DataContract]
public class Example
{

    [DataMember(Name="registrant_contacts")]
    public IList<RegistrantContact> registrant_contacts { get; set; }
}

Sample Serialize Code

public static async Task<Example> GetExample() {
    Example record = new Example();

    using ( WebClient wc = new WebClient() ) {
        wc.Headers.Add( "Accept", "application/json" );

        try {
            DataContractJsonSerializer ser = new DataContractJsonSerializer( typeof( Example ) );
            using ( Stream s = await wc.OpenReadTaskAsync( "https://example.com/sample.json" ) ) {
                record = ser.ReadObject( s ) as Example;
            }
        } catch ( SerializationException se ) {
            Debug.WriteLine( se.Message );
        } catch ( WebException we ) {
            Debug.WriteLine( we.Message );
        } catch ( Exception e ) {
            Debug.WriteLine( e.Message );
        }
    }
    return record;
}

Objective

To change

public IList<RegistrantContact> registrant_contacts { get; set; }

Into

public RegistrantContact registrant_contacts { get; set; }

By altering the [DataMember(Name="registrant_contacts")] line so it uses the first element from the registrant_contacts array as the only result during the transform.

Result, means that instead of calling response.registrant_contacts[0] to access the nested properties id, type, name, etc - I can simply call response.registrant_contacts

Answer 1

You can in two ways - first is to temporary store the data into some list and then to say .FirstOrDefault(); or second is directly to try saying it, but I believe you will have complications. So, just create a temporary list and the extract everything what you need from it. The the data contract could be whatever you like.