using System;

using System.Collections.Generic;

using Newtonsoft.Json;

​

public class Program

{

    internal class ElementId

    {

      public string UniqueId { get; set; }

    }

​

    internal class InputCache

    {

      public string ModelId { get; set; }

      public ElementId[] ElementIds { get; set; }

    }

    public static void Main()

    {

        var json = "{'ModelId':'dXJuOmFkc2sud2lwcHJvZDpmcy5maWxlOnZmLjNSTzhMWmtUVGVHM3p1M1FoNjRGM3c_dmVyc2lvbj0x','ElementIds':[{'UniqueId':'ca5762b5-0f46-4a2f-8599-1d1a5dd19a81-00024b8c'},{'UniqueId':'91e18c07-1bae-4949-a093-e0a4552bb478-000241ea'}]}";

        var obj = JsonConvert.DeserializeObject<InputCache>(json);

        foreach(var id in obj.ElementIds) {

            Console.WriteLine(id.UniqueId);

        }

    }

}

​

​