Excel VBA If Then函数取决于单元格值

Question

I want to calculate a price based on a proposed discount % or calculate a discount based on a proposed price.

I need users to be able to use either parameter and adjust back and forth to determine their ideal price.

I have coded the formulas so that nothing is overwritten by the user but have a problem as the 'value if false' element of the "IF" formula is dependent on a zero value in one column and so resets if the user doesn't manually adjust this before inputting a figure into another. This results in the new figure being reset.

Ideally I would like the sheet to reset the value in column "Proposed Promo POR%" to zero if a value is input in "Promo Price per Unit". Is this possible?

This is the code I have at the moment.

    Private Sub Worksheet_SelectionChange(ByVal Target As Range)

If Intersect(Target, Range("b21:b26")) Is Nothing Then Exit Sub

Application.EnableEvents = False
ActiveSheet.Range("$i21:$i26").Formula ="=IF(Proposal!$b21>Formulae!$a$5,Proposal!$g21-(Proposal!$g21*Proposal!$b21),  (Proposal!$g21-Proposal!$i21)/Proposal!$g21)"
Application.EnableEvents = True

End Sub

For clarity Formulae!$a$5 is zero and it is column $i21:$i26 that the user will enter a price in if they want to. If they do enter something here then column b should reset to zero.

This is a screenshot of the columns and headers in my sheet

Answer 1

The Worksheet_Change event will help you. Worksheet_SelectionChange fires each time a user changes the active cell , whereas Worksheet_Change fires anytime a user makes an edit to any cell(s) .

Private Sub Worksheet_Change(ByVal Target As Range)

If Not Intersect(Target, Range("$i21:$i26"")) Is Nothing _ 
    And Target.Rows.Count = 1 and Target.Columns.Count = 1 Then
    'assumes event will fire only on changing one cell at a time

    Application.EnableEvents = False
    Target.Offset(0,-7).Value = 0
    Application.EnableEvents = True

End If

End Sub