SpaceViewModel

using System.Net.Http;
using Newtonsoft.Json;
using ParseJsonData.Models;
using System.Threading.Tasks;
using System.Collections;
using System.Collections.Generic;

namespace ParseJsonData.ViewModels
{
    public class SpaceViewModel
    {
        IEnumerable _posts;

        public async Task<IEnumerable<Post>> GetPostsAsync()
        {
            if (this._posts != null)
                return _posts;

            this._posts = new List<Post>();

            var client = new HttpClient();
            var myjsondata = await client.GetAsync("http://lyon.us.com/simpledata.json");
            myjsondata.EnsureSuccessStatusCode();

            var spacesJson = await myjsondata.Content.ReadAsStringAsync();
            var rootObject = JsonConvert.DeserializeObject<RootObject>(spacesJson);

            foreach (var space_json in rootObject.posts)
            {
                //I want to get the "title";
                //"value" if the "key" is city and country
                //and put into ObservableCollections so that can Bind in my Listview
                //Can someone help me please,
                    this._posts.add(space_json);
            }

            return _posts;
        }
    }
}