You should look at the
ICollectionView
.
This is great for filtering data used in WPF!
However, a little more detail would have been nice. i.e what are you trying to do? what have you tried etc, are you using MVVM / Code behind!!
ICollectionView view = CollectionViewSource.GetDefaultView(newValue);
IEqualityComparer<string> comparer = StringComparer.InvariantCultureIgnoreCase;
view.Filter = o => {
Person p = o as Person;
return p.FirstName.Contains(SearchedText, comparer)
|| p.LastName.Contains(SearchedText, comparer);
}</string>