Alternative to Application.Volatile to auto update UDF [duplicate]

Answer 1

You may have already found out that changing a cell's interior color doesn't fire a Sub Worksheet_Change(...). As no value is changed, nothing gets recalculated. In this case not even the Application.Volatile is of help.

The best approach might be to use a Worksheet_SelectionChange(...), eventually in combination with Worksheet_Activate(...) and Worksheet_Deactivate(...) (to have the sheet clean upon entry and leave) to call for an enforced recalculation, e.g.

Sub DoMyRecalc()
    ' Range("OutputRange").Calculate ' all uses of countCcolor() within that range
    ' [H3].Calculate                 ' countCcolor() only used in cell H3
End Sub


Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    DoMyRecalc
End Sub

Private Sub Worksheet_Activate()
    DoMyRecalc
End Sub

Private Sub Worksheet_Deactivate()
    DoMyRecalc
End Sub