Forums | NoesisGUI

CollectionViewSource.GetDefaultView

public class FilteredObservable<T> : INotifyPropertyChanged
{
    private ObservableCollection<T> _baseCollection;
    public ObservableCollection<T> BaseCollection
    {
        get
        {
            return _baseCollection;
        }
        set
        {
            // emulate VB's "with events" properties.
            if (null != _baseCollection)
                _baseCollection.CollectionChanged -= _baseCollection_CollectionChanged;

            _baseCollection = value;
            _baseCollection.CollectionChanged += _baseCollection_CollectionChanged;

            NotifyPropertyChange("BaseCollection");
            NotifyPropertyChange("Items");
        }
    }

    public IEnumerator<T> Items
    {
        get
        {
            foreach(var x in _baseCollection)
            {
                if (FilterFunction(x)) // replace true with whatever filter logic you need.
                    yield return x;
            }
        }
    }

    private void _baseCollection_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        NotifyPropertyChange("Items");
    }

    public FilteredObservable(ObservableCollection<T> collection)
    {
        BaseCollection = collection;
        FilterFunction = (e) => { return true; };
    }

    public FilteredObservable()
    {
        BaseCollection = new ObservableCollection<T>();
        FilterFunction = (e) => { return true; };
    }

    protected void NotifyPropertyChange(string name)
    {
        if (null != PropertyChanged)
            PropertyChanged(this, new PropertyChangedEventArgs(name));
    }

    public Func<T, bool> FilterFunction;
    public event PropertyChangedEventHandler PropertyChanged;
}