CollectionViewSource, how to filter data?

Al last I have found a solution, as posted also in this question to explicitly declare the type of the Collection:

CollectionViewType="ListCollectionView"

So in XAML added the Collection type:

<CollectionViewSource x:Key="tSCHEDEViewSource" d:DesignSource="{d:DesignInstance my:TSCHEDE,  CreateList=True}" CollectionViewType="ListCollectionView">
    </CollectionViewSource>

And in code now the Event Handler works:

myCollectionViewSource.Filter += new FilterEventHandler(filterSource);

The only regret is that I did not understand why, for something apparently so simple, I have to force it "by hand" in XAML ??? To me this seems like an hack, and also very error prone...

Check this

1) CollectionView Filtering

Filtering requires a delegate (Predicate) based on which the filter will occur. The Predicate takes in the item an based on the value true or false it returns, it selects or unselect an element.

this.Source.Filter = item => {
    ViewItem vitem = item as ViewItem;
    return vItem != null && vitem.Name.Contains("A");
};

2) FIltering the data Dynamically