vba does not work in excel 2016

[cds]

I have the following vba which works perfecctly ok excel 2007 but when use it excel 2016 pc , excel sheet works very very slowly and macros does get updated . Please help me out

Function Lookup_concatn(Search_stringA As String, Search_in_colA As Range, _
Search_stringB As String, Search_in_colB As Range, Return_val_col As Range)


Dim i As Long
Dim result As String


For i = 1 To Search_in_colA.Count
If Search_in_colA.Cells(i, 1) = Search_stringA And _
Search_in_colB.Cells(i, 1) = Search_stringB Then
result = result & " " & Return_val_col.Cells(i, 1).Value
End If
Next i


Lookup_concatn = (result)


End Function

thanks

 

[Yongle]

try..

Function Lookup_concatn(Search_stringA As String, Search_in_colA As Range, _
                    Search_stringB As String, Search_in_colB As Range, Return_val_col As Range)

Dim a() As Variant, b() As Variant, c() As Variant
Dim i As Long, result As String

a = Search_in_colA.Value
b = Search_in_colB.Value
c = Return_val_col.Value

For i = 1 To UBound(a)
    If a(i, 1) = Search_stringA And b(i, 1) = Search_stringB Then result = result & " " & c(i, 1)
Next

Lookup_concatn = (result)

End Function