Option Explicit
Public Sub Test()
Dim folder1 As Outlook.Folder
Dim folder2 As Outlook.Folder
Set folder1 = ...
Set folder2 = ...
Dim colAllMailItems As VBA.Collection
Call AddMailItemsFromFolder(folder1, colAllMailItems)
Call AddMailItemsFromFolder(folder2, colAllMailItems)
Dim objMailItem As Outlook.MailItem
For Each objMailItem In colAllMailItems
Debug.Print objMailItem.Parent.Name, objMailItem.Subject
Next
End Sub
Public Sub AddMailItemsFromFolder(ByVal Folder As Outlook.Folder, ByRef MailItemCollection As VBA.Collection)
If MailItemCollection Is Nothing Then
Set MailItemCollection = New VBA.Collection
End If
Dim objItem As Object
For Each objItem In Folder.Items
If TypeOf objItem Is Outlook.MailItem Then
Call MailItemCollection.Add(objItem)
End If
Next
End Sub