VBA：是否可以创建一个行为类似于集合的类模块？

Question

我想知道是否可以创建我自己的类，它的行为就像一个集合。最好在示例中显示：

我目前的知识：

类模块MyClass

Public oCollection As Collection
Public OtherData as Long
... 'Another Variables, Properties, Functions and Subs

模块

...
For Each oItem In MyClass.oCollection 'I need to address Collection inside the object
  If oItem.OtherData = 0 Then
...

我想要达到的目标：

...
For Each oItem In MyClass 'Want to be able to iterate over oCollection just from Class
  If oItem.OtherData = 0 Then
...

感谢您的建议。

Answer 1

您可以通过使用 Scripting.Dictionary 和 .items 或 .Keys 来避免 @CristianBuse 描述的错误。使用 for each 返回可以迭代的数组的方法。

在回答您的问题时，包装集合或脚本字典是一种很好的做法，因为它允许您对主机集合进行强类型化。您还可以使用包装代码为您的输入值添加验证或扩展主机集合的功能

下面的代码显示了脚本字典的包装、add 方法的验证以及简化向脚本字典添加数据的扩展。这些只是说明一点的例子

Option Explicit

Private Type State

    Host                As scripting.Dictionary
    
End Type

Private s               As State

Private Sub Class_Initialize()

    Set s.Host = New scripting.Dictionary
    
End Sub


Public Property Get Item(ByVal ipKey As Long) As String
    Item = s.Host.Item(ipKey)
End Property

Public Property Let Item(ByVal ipValue As String, ByVal ipKey As Long)
    s.Host.Item(ipKey) = ipValue
End Property


Public Sub Add(ByVal ipKey As Long, ByVal ipValue As String)

    If ipKey > 10 Then
    
        Err.Raise _
            5 + vbObjectError, _
            "Size Error", _
            "Object based on Class " & TypeName(Me) & " is limited to 0-9 members"
            
        End
        
    End If
    
    s.Host.Add ipKey, ipValue
    
End Sub

Public Sub AddByIndex(ByVal ipArray As Variant)

    Dim myArray As Variant
    
    If Not IsArray(ipArray) Then
    
        myArray = Array(ipArray)
        
    Else
    
        myArray = ipArray
        
    End If
    
    Dim myNextKey As Long
    myNextKey = s.Host.keys(s.Host.Count - 1)
    Do While s.Host.Exists(myNextKey)
    
        myNextKey = myNextKey + 1
        
    Loop
    
    
    Dim myItem As Variant
    For Each myItem In myArray
    
        s.Host.Add myNextKey, myItem
        myNextKey = myNextKey + 1
        
    Next
        
End Sub

Public Function Items() As Variant
    Items = s.Host.Items
End Function

所以你现在可以做

oclass.addbyindex Range("A1:A42").value

和

Dim myItem as Variant
For Each myItem in oClass.Items