I prefer early binding for Dictionary. In VBA Editor, pick Tools > References > Microsoft Scripting Runtime.
Make your Class A like this:
Public currentRowList As Scripting.Dictionary
Private Sub Class_Initialize()
Set currentRowList = New Scripting.Dictionary
Now put this in a standard module:
Dim a1 As A: Set a1 = New A
'use the Add method
a1.currentRowList.Add "key", 1
'or use a1.currentRowList.Item("key") = 1
'but not a1.currentRowList("key") = 1
Debug.Print a1.currentRowList.Keys(0), _
The tutorial Excel VBA Dictionary Keys and Items uses statements like
dict("Alice") = "555-778-0131"
which are OK if Item is the default property of dict. But this does not work when your Dictionary is defined in a class module. The tutorial would be more correct if such statements were changed to
dict.Item("Alice") = "555-778-0131"