CollectionView.DeferRefresh（）は例外をスローします

Question

大量のinOtifyChangeDpropertiesイベントがあるため、多くのUI更新プログラムがある場合があります。その場合、すべてのプロパティがバッチ内のように設定されている場合に一度だけUIへの変更を送信したい場合があります。

ViewCollectionのリフレッシュを延期する方法を説明するこの素晴らしい記事を見つけました：

http://marlongrech.wordpress.com/2008/11/22 / ICollectionView - 説明/

しかし、ビューが延期されたときに例外が得られ、コレクションに何かを追加しようとします。なぜこれを許可すべきかはわかりません。それは最初の場所での全体のポイントです。

InvalidOperationException： の内容または現在の位置を変更または確認できない 更新中のCollectionViewは延期されています。

誰もがこの問題を解決する方法を知っていますか？ 多くの感謝、

Answer 1

Yes, don't modify the collection in question. I think that you are misunderstanding the purpose of a collection view. This is what MSDN says;

You can think of a collection view as a layer on top of a binding source collection that allows you to navigate and display the collection based on sort, filter, and group queries, all without having to manipulate the underlying source collection itself.

So in short, don't defer the refresh until you are done adding and removing, and otherwise manipulating your collection.

Answer 2

I think you are misunderstanding or misrepresenting the MSDN help on the subject. They are saying that you don't have to modify the underlying collection to sort or filter. They are not saying that you can't modify the underlying collection. The OP has a very valid point. We have a large collection that has been sorted and filter for the user and it is displayed in a list box. When the user selects a range of those records and wants to delete them, we are forced into a situation where the ListCollectionView refreshs view for every item that was deleted.

I think the OP's question is very valid. The performance is horrendous because we have multiple filters on a huge set of data. The DeferRefresh has a real purpose on a class like the ListCollectionView, but in inexplicably diabled for inserts and deletes, when you need it the most.