This sample illustrates how we can simply bring more complex data types into Azure Mobile Services.

Windows8ForAzureMobileServicesConverters.cs

namespace Sample
{
    using System;
    using System.Runtime.Serialization;
    using System.Xml.Linq;
    using Windows.Data.Json;
    using Microsoft.WindowsAzure.MobileServices;

    /// <summary>
    /// This sample illustrates how we can simply bring more complex data types into Azure Mobile Services. 
    /// <seealso href="http://blogs.msdn.com/b/carlosfigueira/archive/2012/08/30/supporting-arbitrary-types-in-azure-mobile-services-managed-client-simple-types.aspx"/>
    /// </summary>
    public class CustomConvertedData
    {
        public int Id { get; set; }

        [DataMember(Name = "xml")]
        [DataMemberJsonConverter(ConverterType = typeof(XElementConverter))]
        public XElement SerializedXml { get; set; }

        [DataMember(Name = "octetstream")]
        [DataMemberJsonConverter(ConverterType = typeof(ByteArrayConverter))]
        public byte[] Octets { get; set; }
    }

    public class ByteArrayConverter : DataMemberJsonConverterBase<byte[]>
    {
        protected override byte[] tFromString(string s) { return Convert.FromBase64String(s); }
        protected override string stringFromT(byte[] t) { return Convert.ToBase64String(t); }
    }

    public class XElementConverter : DataMemberJsonConverterBase<XElement>
    {
        protected override XElement tFromString(string s) { return XElement.Parse(s); }
        protected override string stringFromT(XElement t) { return t.ToString(); }
    }

    public abstract class DataMemberJsonConverterBase<T> : IDataMemberJsonConverter
    {
        private static readonly IJsonValue NullJson = JsonValue.Parse("null");

        protected abstract T tFromString(string s);
        protected abstract string stringFromT(T t);

        public object ConvertFromJson(IJsonValue value)
        {
            T t = default(T);
            if (value != null && value.ValueType == JsonValueType.String)
            {
                t = tFromString(value.GetString());
            }

            return t;
        }

        public IJsonValue ConvertToJson(object instance)
        {
            if (instance is T)
            {
                T t = (T)instance;
                return JsonValue.CreateStringValue(stringFromT(t));
            }
            else
            {
                return NullJson;
            }
        }
    }
}