ObservableCollection和Handlers

Question

说，我有一个ObservableCollection

Class Person
  Name
  Event DidSomething

Class House
  WithEvents People as ObservableCollection(of Person)

  Sub OnPersonDidSomething(p as Person)
    Console.WriteLine("{0} did something", p.Name)

现在，我应该如何实现此ObservableCollection的处理程序？

Private Sub People_CollectionChanged( _ 
  sender As Object, _ 
  e As NotifyCollectionChangedEventArgs) Handles People.CollectionChanged

Select Case e.Action
  Case Specialized.NotifyCollectionChangedAction.Add
    For Each mp As Person In e.NewItems
      RemoveHandler mp.DidSomething, AddressOf OnPersonDidSomething
      AddHandler mp.DidSomething, AddressOf OnPersonDidSomething
    Next mp

  Case Specialized.NotifyCollectionChangedAction.Remove
    For Each mp As Person In e.NewItems
      RemoveHandler mp.DidSomething, AddressOf OnPersonDidSomething
    Next mp
End Select

End Sub

这是对的吗？ Move, Replace, Reset行动的内容是什么？

Answer 1

这是正确的。

对于Replace，您应该从旧项目中删除处理程序并将其添加到新项目中。

对于Reset，您应该感到恐慌，因为您无法知道删除或添加了哪些项目。