Here is the follow on to my last post about CollectionView filtering in WPF. This posts shows how to filter a CollectionViewSource object as apposed to a ListCollectionView which the last post covered. CollectionViewSource is mainly used when you want to set up grouping or sorting in XAML (Here is an example). The way you filter a CollectionViewSource in code is different than how you filter a ListCollectionView.  

        CollectionViewSource _view;

        public Window1()
        {
            InitializeComponent();

            string[] myValues = new string[] { "Red Car", "Red Truck", "Blue Car", "Yellow Truck" };

            _view = new CollectionViewSource();
            
            _view.Source = myValues;

            this.DataContext = _view;
        }


        private void FilterTrucks(Object sender, RoutedEventArgs args)
        {
            if (ShowTrucks.IsChecked == true)
                _view.Filter += new FilterEventHandler(IsValueTruck);
            else
            {
                // Remove the filter
                _view.Filter -= new FilterEventHandler(IsValueTruck);
            }
        }


        public void IsValueTruck (object sender, FilterEventArgs e)
        {
            if (e.Item.ToString().Contains("Truck"))
            {
                e.Accepted = true;
            }
            else
            {
                e.Accepted = false;
            }
        }

If you want see what the app looks like when the filter is used see my last post. The app works the same way.