UDF returns the same value everywhere

Question

I am trying to code in moving average in vba but the following returns the same value everywhere.

Function trial1(a As Integer) As Variant
    Application.Vo         


        

Answer 1

The ActiveCell property does not belong in a UDF because it changes. Sometimes, it is not even on the same worksheet.

If you need to refer to the cell in which the custom UDF function resides on the worksheet, use the Application.Caller method. The Range.Parent property can be used to explicitly identify the worksheet (and avoid further confusion) in a With ... End With statement.

Function trial1(a As Integer) As Variant

    Application.Volatile
    Dim rng As Range
    with Application.Caller.Parent
        Set rng = .Range(.Cells(Application.Caller.Row, 2), _
                         .Cells(Application.Caller.Row - a + 1, 2))
        trial1 = (Application.Sum(rng)) * (1 / a)
    end with

End Function

You've applied the Application.Volatile¹ method but allowed the range to be averaged to default to the ActiveSheet property by not explcitly specifying the parent worksheet.

The average is computed with the Excel Application object returning a SUM function's result and some maths. The same could have been returned in one command with the worksheet's AVERAGE function but blank cells would be handled differently.

        trial1 = Application.Average(rng)

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¹ _{Volatile functions recalculate whenever anything in the entire workbook changes, not just when something that affects their outcome changes.}