需要帮助将C＃转换为VB [英] Need help translating C# to VB

问题描述

我正在查看这个博客，我正在尝试将代码片段转换为VB。

I am looking at this blog, and I am trying to translate the snippet to VB.

我在此行遇到困难：

NotifyCollectionChangedEventHandler handlers = this.CollectionChanged;

注意：CollectionChanged是此事件（ this是对 ObservableCollection< T> ）。

NOTE: CollectionChanged is an event of this ('this' is an override of ObservableCollection<T>).

推荐答案

引发事件， OnCollectionChanged 应该可以正常工作。如果您想查询，则必须更加滥用并使用反射（对不起，示例是C＃，但实际上应该是相同的-我在这里不使用任何特定于语言的功能）：

To raise the event, OnCollectionChanged should work fine. If you want to query it you have to get more abusive and use reflection (sorry, example is C# but should be virtually identical - I'm not using any language-specific features here):

NotifyCollectionChangedEventHandler handler = (NotifyCollectionChangedEventHandler)
    typeof(ObservableCollection<T>)
    .GetField("CollectionChanged", BindingFlags.Instance | BindingFlags.NonPublic)
    .GetValue(this);

et voila;处理程序（通过 GetInvocationList（））。

et voila; the handler or handlers (via GetInvocationList()).

基本上，在您的示例中（关于该帖子），使用：

So basically in your example (regarding that post), use:

Protected Overrides Sub OnCollectionChanged(e As NotifyCollectionChangedEventArgs)
    If e.Action = NotifyCollectionChangedAction.Add AndAlso e.NewItems.Count > 1 Then
        Dim handler As NotifyCollectionChangedEventHandler = GetType(ObservableCollection(Of T)).GetField("CollectionChanged", BindingFlags.Instance Or BindingFlags.NonPublic).GetValue(Me)
        For Each invocation In handler.GetInvocationList
            If TypeOf invocation.Target Is ICollectionView Then
                DirectCast(invocation.Target, ICollectionView).Refresh()
            Else
                MyBase.OnCollectionChanged(e)
            End If
        Next
    Else
        MyBase.OnCollectionChanged(e)
    End If
End Sub

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