A Windows Phone 7 App from the Ground Up

using System;
using System.ComponentModel;
using System.Collections.Generic;
using System.Device.Location;
using System.Diagnostics;

using MyLastFm.Model;

namespace MyLastFm.ViewModel
{
    public class CalendarViewModel : DisplayableViewModel<User>
    {
        private ImmediateLocation _location;
        private GeoCoordinate _coordinate;

        public CalendarViewModel(User u)
            : base(u)
        {
            ViewModels.Args["user"] = Item.Name;
            ViewModels.Add<Event>(new ItemsSourceViewModel<User, Event>("CalendarEvents", item => new EventViewModel(item)));
            ViewModels.Add<Event>(new ItemsSourceViewModel<User, Event>("RecommendedEvents", item => new EventViewModel(item)));

            _location = new ImmediateLocation(SetLocation);
        }

        public override void Refresh()
        {
            _coordinate = null;
            _location.GetLocation(); 
            
            ViewModels.Args["user"] = Item.Name;

            base.Refresh();
        }

        protected override void OnAuthenticationChanged()
        {
            if (Authenticated)
                ViewModels.Args["user"] = Item.Name;

            base.OnAuthenticationChanged();
        }

        public AppViewModel CalendarEvents
        {
            get
            {
                return ViewModels.GetViewModel<Event>("CalendarEvents", Item.CalendarEvents);
            }
        }

        public AppViewModel RecommendedEvents
        {
            get
            {
                return ViewModels.GetViewModel<Event>("RecommendedEvents", Item.RecommendedEvents);
            }
        }

        private ItemsSourceViewModel<User, Event> _NearbyEvents = new ItemsSourceViewModel<User, Event>("NearbyEvents", item => new EventViewModel(item));
        public AppViewModel NearbyEvents
        {
            get
            {
                _location.GetLocation();
                return _NearbyEvents;
            }
        }

        private void RefreshNearby()
        {
            if (_coordinate != null)
            {
                Item.NearbyEvents.Clear();

                var args = new Dictionary<string, string>();
                args.Add("lat", _coordinate.Latitude.ToString());
                args.Add("long", _coordinate.Longitude.ToString());

                _NearbyEvents.Load(args, Item.NearbyEvents);
            }
        }

        void SetLocation(GeoCoordinate coordinate)
        {
            _coordinate = coordinate;
            RefreshNearby();
        }

        public override void Cleanup()
        {
            if (_location != null)
                _location.Dispose();

            base.Cleanup();
        }
    }
}