ItemsControl.ItemsSource MVVM性能 [英] ItemsControl.ItemsSource MVVM performance

问题描述

我有一个(非虚拟化的)ItemsControl，它将其ItemsSource绑定到ViewModel实例的ObeservableCollection.现在，一旦加载了大量Model实例，就需要将所有ViewModel组件添加到该ObservableCollection中.如何在不使UI线程挂起的情况下添加大量ViewModel?

I have an (non-virtualized) ItemsControl that binds its ItemsSource to a ObeservableCollection of ViewModel instances. Now once the large amount Model instances is loaded all the ViewModel complemnents needs to be added to that ObservableCollection. How can I add a large amount of ViewModels without making the UI Thread hang?

我想UI线程会挂起，因为每次添加新项目时，ItemsControl都需要更新自身，并一遍又一遍地进行布局等.

I suppose the UI Thread hangs because each time a new item is added the ItemsControl needs to update itself and does layout etc. over and over again.

• 我应该暂停绑定吗? 项目然后恢复?如果可以，怎么办?
• 我应该覆盖 ObservableCollection实现一个 AddRange，所以只有1 CollectionChanged 为添加多个事件而触发了该事件 项目?或者替代 整个收藏?
• 还是更好 分别添加每个项目并调用 调度程序.为每个项目调用 分别地?所以我会解除封锁

• Should I suspend the binding add all items and then resume? If so, how?
• Should I override the ObservableCollection to implement an AddRange so only 1 CollectionChanged Event is fired for adding multiple items? Or alternatively just replace the whole collection?
• Or is it better to add each items separately and call Dispatcher.Invoke for each item separately? So I would unblock frequently.

您如何处理无法虚拟化的大型动态列表?

How do you handle large dynamic lists that can not be virtualized?

推荐答案

您可以创建一个从 ObservableCollection ，使您可以临时暂停 CollectionChanged 这样的事件:

You can create a a class derived from ObservableCollection which allows you to temporarily suspend CollectionChanged events like this:

public class SuspendableObservableCollection : ObservableCollection
{
    private bool suspended;

    public bool Suspended 
    {
        get
        {
            return this.suspended;
        }
        set
        {
            this.suspended = value;
            OnCollectionChanged(new NotifyCollectionChangedEventArgs(
                NotifyCollectionChangedAction.Reset));
        }
    }

    protected override void OnCollectionChanged(
        NotifyCollectionChangedEventArgs args)
    {
       if (!Suspended)
       {
           base.OnCollectionChanged(args);
       }
    }
}

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