Sub AddProcedureToSheetModule()
Dim VBCodeMod As CodeModule
Dim LineNum As Long

    Set VBCodeMod = ThisWorkbook.VBProject.VBComponents("Sheet1").CodeModule

    With VBCodeMod
        LineNum = .CountOfLines +  1 
        .InsertLines LineNum, _
            "Private Sub Worksheet_Change(ByVal Target As Range)" & Chr( 13 ) & _
            "Const InputDataRow = 3" & Chr( 13 ) & _
            "Const ArticleColumnNumber = 2" & Chr( 13 ) & _
            "Const FirstDataRow = 5" & Chr( 13 ) & _
            "Const AmountColumnNumber = 3" & Chr( 13 ) & _
            "Dim LastDataRow As Long" & Chr( 13 ) & _
            "Dim RowIndex As Long" & Chr( 13 ) & _
            "" & Chr( 13 ) & _
            "    If Target.Count > 1 Then Exit Sub" & Chr( 13 ) & _
            "    If Target.Value = """" Then Exit Sub" & Chr( 13 ) & _
            "" & Chr( 13 ) & _
            "    LastDataRow = Columns(ArticleColumnNumber).SpecialCells(xlCellTypeLastCell).Row" & Chr( 13 ) & _
            "" & Chr( 13 ) & _
            "    If Target.Address = Range(""ValidationListBox"").Address Then" & Chr( 13 ) & _
            "        RowIndex = Range(Cells(FirstDataRow, ArticleColumnNumber), Cells(LastDataRow, ArticleColumnNumber)).Find(Range(""ValidationListBox"").Value).Row" & Chr( 13 ) & _
            "        Range(""InputCell"").Value = Cells(RowIndex, AmountColumnNumber).Value" & Chr( 13 ) & _
            "    ElseIf Target.Address = Range(""InputCell"").Address Then" & Chr( 13 ) & _
            "        RowIndex = Range(Cells(FirstDataRow, ArticleColumnNumber), Cells(LastDataRow, ArticleColumnNumber)).Find(Range(""ValidationListBox"").Value).Row" & Chr( 13 ) & _
            "        Cells(RowIndex, AmountColumnNumber).Value = Range(""InputCell"").Value" & Chr( 13 ) & _
            "    End If" & Chr( 13 ) & _
            "" & Chr( 13 ) & _
            "End Sub"
    End With

End Sub