Adding and removing multiple items in the ItemCollectionView<T> takes too long

[sforsten]

Similar to ticket #1963, it takes to long to add and remove multiple items in the ItemCollectionView<T> and in its derived views (e.g. CheckedItemListView, ClassificationEnsembleSolutionModelView.ModelsView, RegressionEnsembleSolutionModelView.ModelsView) and in views where the IItemCollection<T> is used (e.g. RunCollectionView).

The reason is, that the interface IItemCollection<T> is used to add and remove items. It only contains methods to add/remove one item at a time, although the concrete classes like ItemCollection<T> contain methods to add/remove a range of items, which would decrease the runtime drastically.

[gkronber]

Add missing methods to the interface.

[mkommend]

Replying to gkronber:

Add missing methods to the interface.

It is not possible to add the methods for batch manipulation, because all ReadOnlyCollections and Set classes derive from IItemCollection and batch updates are not easily defined for them.

Another solution would be to add a check for the concrete class and call the appropriate methods directly.

[mkommend]

r9613: Adapted ItemCollectionView and RunCollectionView to use batch events if the content supports them.

[gkronber]

Reviewed and tested r9613.

[gkronber]

I found that similar code also exists for instance in ItemListView. Is it useful to make the same change in all views that support AddRange/RemoveRange?

[mkommend]

Replying to gkronber:

I found that similar code also exists for instance in ItemListView. Is it useful to make the same change in all views that support AddRange/RemoveRange?

Yes, the ItemsListView should also be adapted. However, I found another issue, which I don't know how to resolve correctly. If a collection contains duplicate items, currently the first reference to it is removed, regardless of the selection. So the question is how to deal with duplicates in collections (not only regarding deletion)?

The deletion is handled in a better way in ListViews, because there the items are removed according to their index and so duplicates are no issue.

[gkronber]

We should leave it as it is. The first occurrence of an item should be removed when an item is contained multiple times in a collection.

[mkommend]

Currently the ItemListView performs GUI-triggered modifications based on the index of the item. This is not possible when using batch modification commands => The behavior of the ItemListView would be changed. Therefore, I disapprove using batch commands in the ItemsListView.

[gkronber]

r10495: used the more general type ObservableCollection in ItemCollectionView. In RunCollectionView the type must be RunCollection.

As discussed with mko and sketched in comment:10 we won't change ItemListView.

[gkronber]

r10529: merged r9613 and r10495 from trunk into stable.