Question

I have an instance of an EF entity that im serializing to JSON. Is there any way to add some properties to it, without using a POCO class? Maybe create a new object and attach it, if thats possible?

HttpContext.Current.Response.Write(serializer.Serialize(system.OrderByDescending(s => s.SYSTEM_ID)));

Answer 1

HttpContext.Current.Response.Write(
    serializer.Serialize(
        system.OrderByDescending(s => s.SYSTEM_ID).Select(s => new {
            s.SYSTEM_ID,
            NewProperty = "Foo"
})));

I don’t know where your code gets executed, but using HttpContext Response.Write directly is a bit of a smell.