こんな

gistfile1.txt

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Web.Syndication;

namespace App1
{
    public class TestData : INotifyPropertyChanged
    {
        private SyndicationFeed feed;
        public SyndicationFeed Feed
        {
            get { return this.feed; }
            set
            {
                this.feed = value;
                this.OnPropertyChanged("Feed");
            }
        }

        public async Task Load()
        {
            var r = new SyndicationClient();
            this.Feed = await r.RetrieveFeedAsync(new Uri("http://blogs.msdn.com/b/microsoft_japan_academic/rss.aspx"));
        }

        public event PropertyChangedEventHandler PropertyChanged;
        protected virtual void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}