Excel 通过'传递类对象；属性获取'；在父类中，不影响嵌套的类对象

我有如下定义的类的层次结构

问题：

Private pText As String

Private Sub Class_Initialize()
pText = ""
End Sub

Property Let Text(T As String)
    pText = T
End Property

Property Get Text() As String
    Text = pText
End Property

问题列表：

Private pQList() As New cQuestion
Private pListLen As Integer

Private Sub Class_Initialize()
    pListLen = 0
End Sub

Public Sub AddEnd(Q As String)
    pListLen = pListLen + 1
    ReDim Preserve pQList(1 To pListLen)
    pQList(pListLen).Text = Q
End Sub

Public Function Format() As String
    Dim i As Integer
    If pListLen = 0 Then
        FormatList = "There are no questions in this category" + vbNewLine
    Else
        FormatList = "Questions:" + vbNewLine
        For i = 1 To pListLen
            FormatList = FormatList + "• " + pQList(i).Text + vbNewLine
        Next i
    End If
End Function

C类别：

Private pName As String
Private pQList As New cQuestionList

Private Sub Class_Initialize()
    pName = ""
End Sub

Property Get QuestionList() As cQuestionList
    Set QuestionList = pQList
End Property

Property Let Name(N As String)
    pName = N
End Property

Property Get Name() As String
    Name = pName
End Property

当我试图调用

Category.QuestionList.AddEnd“Question Here”

时， 它不会抛出任何错误。然而，当我随后调用

MsgBox Category.QuestionList.Format时，我得到一个空白的消息框。我不确定这怎么会变成空白，因为格式应该总是返回文本。我在这里做错了什么？我已经看过了在父类中通过let和get传递类对象的其他示例，但看不出我所做的有什么不同。有什么建议吗

示例代码：

Dim C as New cCategory
C.QuestionList.AddEnd "A Question"
C.QuestionList.AddEnd "Another Question"
MsgBox C.QuestionList.Format

将
选项Explicit
放在每个模块的顶部，您将立即看到问题：

Public Function Format() As String
    Dim i As Integer
    If pListLen = 0 Then
        FormatList = "There are no questions in this category" + vbNewLine
           '^^^^ Variable not defined.
    Else
        FormatList = "Questions:" + vbNewLine
        For i = 1 To pListLen
            FormatList = FormatList + "• " + pQList(i).Text + vbNewLine
        Next i
    End If
End Function

您需要将
Public Function Format（）作为字符串
更改为
Public Function FormatList（）作为字符串
，或者将
FormatList
赋值更改为
格式

我个人会使用
格式列表
命名，以避免与
格式
函数发生冲突。
将
选项显式
放在每个模块的顶部，您会立即看到问题：

Public Function Format() As String
    Dim i As Integer
    If pListLen = 0 Then
        FormatList = "There are no questions in this category" + vbNewLine
           '^^^^ Variable not defined.
    Else
        FormatList = "Questions:" + vbNewLine
        For i = 1 To pListLen
            FormatList = FormatList + "• " + pQList(i).Text + vbNewLine
        Next i
    End If
End Function

您需要将
Public Function Format（）作为字符串
更改为
Public Function FormatList（）作为字符串
，或者将
FormatList
赋值更改为
格式

我个人会使用
FormatList
命名，以避免与
Format
函数发生冲突