作者： 老王

一、首先创建三个基础类（ClassA、ClassB、ClassC）

‘ ClassA.cls
‘（空类，可根据需要添加属性或方法，见 建立类模块）

‘ ClassB.cls
‘（空类，可根据需要添加属性或方法，见 建立类模块）

‘ ClassC.cls
‘（空类，可根据需要添加属性或方法，见 建立类模块）

二、创建主类（MainClass）包含三个集合

‘ MainClass.cls
Option Explicit

Private m_colItemsA As Collection
Private m_colItemsB As Collection
Private m_colItemsC As Collection

‘ 类初始化时创建集合
Private Sub Class_Initialize()
Set m_colItemsA = New Collection
Set m_colItemsB = New Collection
Set m_colItemsC = New Collection
End Sub

‘ 添加ClassA实例到集合A
Public Sub AddItemA(objA As ClassA)
m_colItemsA.Add objA
End Sub

‘ 添加ClassB实例到集合B
Public Sub AddItemB(objB As ClassB)
m_colItemsB.Add objB
End Sub

‘ 添加ClassC实例到集合C
Public Sub AddItemC(objC As ClassC)
m_colItemsC.Add objC
End Sub

‘ 获取集合A（只读）
Public Property Get ItemsA() As Collection
Set ItemsA = m_colItemsA
End Property

‘ 获取集合B（只读）
Public Property Get ItemsB() As Collection
Set ItemsB = m_colItemsB
End Property

‘ 获取集合C（只读）
Public Property Get ItemsC() As Collection
Set ItemsC = m_colItemsC
End Property

‘ 清理资源
Private Sub Class_Terminate()
Set m_colItemsA = Nothing
Set m_colItemsB = Nothing
Set m_colItemsC = Nothing
End Sub

三、使用示范

Dim mainObj As New MainClass
Dim objA As New ClassA
Dim objB As New ClassB
Dim objC As New ClassC

‘ 添加对象到各个集合
mainObj.AddItemA objA
mainObj.AddItemB objB
mainObj.AddItemC objC

‘ 遍历集合示例
Dim item As Object
For Each item In mainObj.ItemsA
‘ 处理ClassA实例
Next

For Each item In mainObj.ItemsB
‘ 处理ClassB实例
Next

For Each item In mainObj.ItemsC
‘ 处理ClassC实例
Next

四、代码说明

1. 三个基础类（ClassA/B/C）可根据实际需求添加成员
2. MainClass使用Collection对象管理三个不同类型的集合
3. 通过AddItemX方法确保类型安全，只能添加指定类型的实例
4. 通过只读属性ItemsX暴露集合的访问
5. 在Class_Terminate中释放集合资源
6. 使用For Each循环可以方便地遍历集合成员

五、注意事项

VB6的集合是1-based索引（从1开始），如果需要更强大的集合操作，可以考虑使用Dictionary对象或自定义集合类。

‘一、建立子类 CAddress.cls
Private m_Street As String
Private m_City As String

Public Property Get Street() As String
Street = m_Street
End Property

Public Property Let Street(ByVal sStreet As String)
m_Street = sStreet
End Property

Public Property Get City() As String
City = m_City
End Property

Public Property Let City(ByVal sCity As String)
m_City = sCity
End Property

‘ 二、建立父类 CPerson.cls
Private m_Address As CAddress ‘ 声明 CAddress 类型的私有变量

‘ 自动初始化 CAddress 实例
Private Sub Class_Initialize()
Set m_Address = New CAddress
End Sub

‘ 清理资源
Private Sub Class_Terminate()
Set m_Address = Nothing
End Sub

‘ 通过 Property Get 公开 CAddress 实例
Public Property Get Address() As CAddress
Set Address = m_Address
End Property

‘ 可选：允许外部设置 CAddress 实例
Public Property Set Address(ByVal objAddress As CAddress)
Set m_Address = objAddress
End Property

‘ 三、在窗体或模块中使用：
Dim person As CPerson
Set person = New CPerson

‘ 设置地址属性
With person.Address
.Street = “123 Main St”
.City = “New York”
End With

‘ 读取地址属性
MsgBox “地址：” & person.Address.Street & “, ” & person.Address.City

‘四、注意事项

Set person.Address = New CAddress ‘ 正确
person.Address = New CAddress ‘ 错误（缺少 Set）