class - Iterating through the Object Browser in VBA

Question

I would like to iterate through members of any class in a referenced library much like is done using the Object Browser. How can this be done using VBA?

Answer 1

Actually, how to do this is undocumented, but is possible. If your looking to implement a for..Each syntax for a collection, then you can do the following:

Option Compare Database
Option Explicit

Public colT       As New Collection

Public Function NewEnum() As IUnknown

   Set NewEnum = colT.[_NewEnum]

End Function

Public Property Get NextItem() As IUnknown
Attribute NextItem.VB_UserMemId = -4
Attribute NextItem.VB_MemberFlags = "40"

   Set NextItem = colT.[_NewEnum]

End Property

Note the Attribute settings in the above. You have to use the SaveAsText and edit code as above in notepad. You then re-import the code using loadfromText in the debug command line. Once you do the above, then you can go:

Dim n       As clstest1
Dim v       As Variant

Set n = New clstest1

[ code here that adds to collection]

For Each v In n
   Debug.Print v
Next

And, if you not looking to use for...each for a collection, you could/can also setup a default property of the class by going:

Public Property Get Item(Optional ndx As Integer = 1) As Variant
Attribute Item.VB_UserMemId = 0
   Select Case ndx
      Case 1: Item = Me.s1
      Case 2: Item = Me.s2
      Case 3: Item = Me.s3
   End Select

End Property

Public Property Get count() As Integer

   count = 3

End Property

Then, you can go:

Dim n       As clstest1
Dim i       As Integer

Set n = New clstest1

For i = 1 To n.count
   Debug.Print n(i)
Next

However, I not aware how you can automatic add each method/member of the class to a built-in object collection automatic (there is no way to serialize this with compiler options, but I have seen code with each procedure having Attribute Item.VB_UserMemId = 1, then 2 then 3). Perhaps someone with more knowledge can jump in).

However, as the above shows, you can implement a for..each for collections. And you can implement an index for each of the properties/methods if you create a custom item property. And, as the above shows, you can even set that item property you create as the default. I put in the "optional", and thus even:

debug.print n

Will work, or

debug.print n.Item(1)