正确使用CancelEventAgrs

我应该如何正确使用CancelEventAgrs/CancelEventHandler?

检查e.Cancel是否总是返回"正确"的结果，即使事件最终可能消耗一些时间?

Class Foo
  Public Event Deleting As System.ComponentModel.CancelEventHandler
  Private myObjectsToDelete As List(Of Object)
  Function DoDelete() As Boolean
    Dim e As New System.ComponentModel.CancelEventArgs
    ' Suppose a time consumming check '
    RaiseEvent Deleting(myObjectsToDelete, e)
    If e.Cancel Then
      Return False
    Else
      myObjectsToDelete.Clear()
      Return True
    End If
  End Function
End Class
Class Bar
  Private WithEvents myFoo As Foo
  Private Sub myFoo_Deleting( _
        sender As Object,
        e As System.ComponentModel.CancelEventArgs) Handles myFoo.Deleting
    Dim objectsList As List(Of Object) = TryCast(sender, List(Of Object))
    Dim objectsToDeleteOK As New List(Of Object)
    For Each o In objectsList
      If CheckIfCanBeDeleted(o) Then
        objectsToDeleteOK.Add(o)
      End If
    Next o
  End Sub
  Private Function CheckIfCanBeDeleted(o As Object) As Boolean
    Dim result As Boolean
    ' TIME CONSUMMING CHECK '
    Return result
  End Function
End Class

p。
我放上c#标签，是因为对一般的。net视图感兴趣，而不仅仅是VB。净一个