.net - 如何明确调用 ItemsCollection.Filter？

Question

我如何明确地调用类似“DoFilter”的东西System.Windows.Controls.ItemCollection？

我将它的过滤器属性设置为谓词。我在谓词中放置了一个断点，它仅在初始化 ItemsCollection 时到达那里，当我调用 m_ItemsCollection.Refresh() 时它不是。

Answer 1

有几种情况 .Refresh() 不起作用，但这确实有效：

collection.Filter = collection.Filter;

几个月前我遇到了这个问题。显然，有一个错误使 ItemsControl 在某些情况下无法可靠地传递 Refresh() 调用。我没有调查细节。

Answer 2

刷新有时不起作用的原因是因为在 ItemsCollection 上使用了此代码：

   /// <summary>
    /// Set/get a filter callback to filter out items in collection.
    /// This property will always accept a filter, but the collection view for the
    /// underlying ItemsSource may not actually support filtering.
    /// Please check <seealso cref="CanFilter"/>
    /// </summary>
    /// <exception cref="NotSupportedException">
    /// Collections assigned to ItemsSource may not support filtering and could throw a NotSupportedException.
    /// Use <seealso cref="CanFilter"/> property to test if filtering is supported before assigning
    /// a non-null Filter value.
    /// </exception>
    public override Predicate<object> Filter
    {
        get
        {
            return (EnsureCollectionView()) ? _collectionView.Filter : MyFilter;
        }
        set
        {
            MyFilter = value;
            if (_collectionView != null)
                _collectionView.Filter = value;
        }
    } 

过滤器设置在基础集合视图上，而不是 ItemsCollection 本身。

然后基本的 Refresh 方法实际上并没有调用 do any to _collectionView，所以 refresh 什么也不做！

/// <summary>
    /// Re-create the view, using any <seealso cref="SortDescriptions"/> and/or <seealso cref="Filter"/>.
    /// </summary>
    public virtual void Refresh()
    {
        IEditableCollectionView ecv = this as IEditableCollectionView;
        if (ecv != null && (ecv.IsAddingNew || ecv.IsEditingItem))
            throw new InvalidOperationException(SR.Get(SRID.MemberNotAllowedDuringAddOrEdit, "Refresh"));

        RefreshInternal();
    }  

很抱歉回答老问题，但觉得值得澄清。