CODEWITHSUNDEEP
c#wpfcollections
Sturm
Sturm

Reputation: 4125

Not able to work with my filtered items

In order to filter an list of objects I've defined this property:

 private ICollectionView _view;
    public ICollectionView View
    {
        get
        {
            return _view;
        }
        set
        {
            _view = value;
            OnPropertyChanged("View");
        }
    }

And then my filter:

  item.View = CollectionViewSource.GetDefaultView(item.myList);

 item.View.Filter = delegate(object o)
 {

           if (myCondition)
      {
         return true;
      }

}

The filter works fine but as ICollectionView is an interface I can't work with my items: if I call them this way:

element1 = item.View[0].SomeProperty;

I recieve 

Cannot apply indexing with [] to an expression of type 'System.ComponentModel.ICollectionView'

I've tried to set in the beginning View not as interface but later I couldn't make the filter work. Doing so and trying to cast:

item.View = (ICollectionView)CollectionViewSource.GetDefaultView(item.myList);

Haven't brought me good results either.

What can I do in order not only to filter (in my case I display the items in a ComboBox) but also work with them... My aim is to be able to make a foreach loop for all elements remaining in the ComboBox. Is this possible?

Upvotes: 0

Views: 72

Answers (2)

Bill Zhang
Bill Zhang

Reputation: 1929

Given List and ICollectionView:

List<SomeType> list;
ICollectionView view=CollectionViewSourse.GetDefaultView(list);
view.Filter=filter;

You can use

var filteredList=view.Cast<SomeType>().ToList();

to enable indexer for filtered collection. The list will change with the collection view. Therefore in some way it is not deterministic. I am not sure but quite interested to know what is your use case to force you to use indexer on collection view.

Upvotes: 0

Joel Lucsy
Joel Lucsy

Reputation: 8706

Store the view separately from the list. Shorthand below, fill in with appropiate INotifyPropertyChanged and such.

List<SomeType> list;
ICollectionView view;

view = list as ICollectionView;
view.Filter = obj => obj.someprop == somevalue;

list[ 10 ].someprop = somevalue

Upvotes: 1

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