TypeOf无法使用Excel工作簿的实现接口的ActiveSheet

Question

我有一个PublicNotCreatable接口PublicInterface

Option Explicit

Sub DoSomething()
End Sub

而在同一工作簿中,我有一个片,Sheet1即器具 PublicInterface

Option Explicit

Implements PublicInterface

Private Sub PublicInterface_DoSomething()
  Beep
End Sub

然后,在Module1,我有代码,试图确定是否ThisWorkbook.ActiveSheet类型PublicInterface

Sub testSheet()

  Dim sht As Object
  For Each sht In ThisWorkbook.Sheets
    'DOES run
    Debug.Print "Enumerated Sheet Is PublicInterface"
  Next sht

  If TypeOf ThisWorkbook.ActiveSheet Is PublicInterface Then
    '*** Doesn't run ***
    Debug.Print "ThisWorkbook.ActiveSheet Is PublicInterface"
  End If

  Debug.Print ThisWorkbook.ActiveSheet.Name
  If TypeOf ThisWorkbook.ActiveSheet Is PublicInterface Then
    'DOES run
    Debug.Print "After getting an ActiveSheet property, ThisWorkbook.ActiveSheet Is PublicInterface"
  End If

  If TypeOf ThisWorkbook.Sheets(ThisWorkbook.ActiveSheet.Name) Is PublicInterface Then
    'DOES Run
    Debug.Print "ThisWorkbook.Sheets(ThisWorkbook.ActiveSheet.Name) Is PublicInterface"
  End If

  If TypeOf ThisWorkbook.Worksheets(ThisWorkbook.ActiveSheet.Name) Is PublicInterface Then
    'DOES Run
    Debug.Print "ThisWorkbook.Worksheets(ThisWorkbook.ActiveSheet.Name) Is PublicInterface"
  End If

  'Force the project to reset
  End

End Sub

如果项目已被重置,似乎TypeOf ThisWorkbook.ActiveSheet Is PublicInterface返回False,但如果删除该End语句(因此项目未重置),并运行代码两次,则返回False第一次,True然后(直到项目重置),因为后续的代码行似乎强制解决了工作表的类型.同样,如果您单步执行代码,它True 每次都会返回.

有趣的是,TypeOf Sheet1 Is PublicInterface似乎工作.此外,在实现接口时,同样的问题并不明显ThisWorkbook,并且使用TypeOf ThisWorkbook Is PublicInterface确实返回True

这闻起来像VBA的bug.我怀疑它与工作表的编译时间有关.这是一个已知的问题？我在检查时做错了ThisWorkbook.ActiveSheet吗？我似乎无法重现与普通班是否这种行为Private还是PublicNotCreatable.

如果我需要检查工作簿的ActiveSheet是否实现了接口,这可能是最安全的方法:

If TypeOf ThisWorkbook.Sheets(ThisWorkbook.ActiveSheet.Name) Is PublicInterface Then