private void LoadDistinctValuesAsync()
		{
			NorthwindDomainContext context = new NorthwindDomainContext();
			
			EntityQuery<DistinctValue> countriesQuery =
				context.GetDistinctValuesQuery("Country");
			context.Load<DistinctValue>(countriesQuery
				, LoadBehavior.RefreshCurrent
				, this.OnDistinctValuesLoaded
				, this.countries);
			
			EntityQuery<DistinctValue> citiesQuery =
				context.GetDistinctValuesQuery("City");
			context.Load<DistinctValue>(citiesQuery
				, LoadBehavior.RefreshCurrent
				, this.OnDistinctValuesLoaded
				, this.cities);
			
			EntityQuery<DistinctValue> contactTitlesQuery =
				context.GetDistinctValuesQuery("ContactTitle");
			context.Load<DistinctValue>(contactTitlesQuery
				, LoadBehavior.RefreshCurrent
				, this.OnDistinctValuesLoaded
				, this.contactTitles);
		}
		public CustomersViewModel()
		{
			NorthwindDomainContext context = new NorthwindDomainContext();
			EntityQuery<DistinctValue> contactTitlesQuery = context.GetDistinctValuesQuery("ContactTitle");
			context.Load<DistinctValue>(contactTitlesQuery
				, LoadBehavior.RefreshCurrent
				, this.OnDistinctContactTitlesLoaded
				, this.contactTitles);
			
			EntityQuery<Customer> getCustomersQuery = context.GetCustomersQuery();
			this.view = new QueryableDomainServiceCollectionView<Customer>(context, getCustomersQuery);
			
			this.view.PageSize = 10;
			this.view.AutoLoad = true;
			this.view.PropertyChanged += this.OnViewPropertyChanged;
			this.view.LoadedData += this.OnViewLoadedData;

			this.loadCommand = new DelegateCommand(this.ExecuteLoadCommand, this.LoadCommandCanExecute);

			this.countrySortDescriptor = new SortDescriptor() { Member = "Country" };
			this.citySortDescriptor = new SortDescriptor() { Member = "City" };

			this.contactTitles = new RadObservableCollection<string>();
			this.contactTitles.Add(CustomersViewModel.ClearSelectionString);
			
			this.contactTitleFilterDescriptor = new FilterDescriptor("ContactTitle", FilterOperator.IsEqualTo, FilterDescriptor.UnsetValue);
			this.view.FilterDescriptors.Add(this.contactTitleFilterDescriptor);
		}