CODEWITHSUNDEEP
c#wpfbindingmvvmcollections
katit
katit

Reputation: 17905

CollectionViewSource does not re-sort on property change

I'm binding ItemsControl to CollectionViewSource. Here is code:

this.Trucks = new ObservableCollection<Truck>();
            foreach (var truck in DataRepository.Trucks.Where(t => t.ReadyDate.Date.Equals(this.Date)))
            {
                this.Trucks.Add(truck);
            }

            this.TrucksSource = new CollectionViewSource { Source = this.Trucks };
            this.TrucksSource.SortDescriptions.Add(new SortDescription("ReadyAddress.Region.RegionNumber", ListSortDirection.Ascending));
            this.TrucksSource.SortDescriptions.Add(new SortDescription("TruckId", ListSortDirection.Ascending));

When I initially bind - sorting works. When I add item to ObservableCollection - it is inserted in proper spot, thats good. But when I change property which I sort by - this item is not being "shifted" in a list.

ReadyAddress.Region.RegionNumber properly raises INotifyPropertyChanged and I see it in bound fields, but order does not change. Do I expect something that shouldn't happen or there is better way to handle this?

Upvotes: 14

Views: 11865

Answers (3)

Shawn Kendrot
Shawn Kendrot

Reputation: 12465

Late answer, but with 4.5 the ListCollectionView (the default implementation for a ListBox and CollectionViewSource.View) new properties were added to make this possible.

You can use the IsListSorting and ListSortingProperties to enable automatic resorting. And no, it does not rebuild the view

list.SortDescriptions.Add(new SortDescription("MyProperty", ListSortDirection.Ascending));
list.IsLiveSorting = true;
list.LiveSortingProperties.Add("MyProperty");

This should resort when the property MyProperty changes.

Upvotes: 13

katit
katit

Reputation: 17905

All answers I found mentioned View.Refresh() but that's not very good solution for big lists. What I ended up doing was to Remove() and Add() this item. Then it was properly repositioned without reloading whole list.

Word of caution! It works for what I do, but in your case removing object and re-adding may cause side effect depending how your code written. In my case it's a list with UI effect where new items show up with transition so refreshing will show transition on whole list where remove/add nicely shows how item get's repositioned.

Upvotes: 5

Bambu
Bambu

Reputation: 548

Have you tried refreshing your collectionviewsource? 

    this.TruckSource.View.Refresh();

Upvotes: 5

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