How do I execute instructions only if the cell value change? - excel

Question

I have a ByVal code to clear the contents of a specific range inside a table, it works. But I need to add a condition for the instructions execute if the RANGE VALUE (content) change, not if I only place the cursor on it.
Also, someone knows how to reference a table column in VBA? Now I'm using an estimated range "C1:C999" but I'll like to use his name "A_[OPERATION]".
This is the code:
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Not Application.Intersect(Range("C1:C999"), Range(Target.Address)) Is Nothing Then
Range(Selection, Selection.End(xlToRight)).ClearContents
End If
End Sub

Answer 1

You could use the change event instead.
Here's a link to the documentation:
https://learn.microsoft.com/en-us/office/vba/api/excel.worksheet.change
Alternatively, you could save the value of your target cell in a variable and check if the value changed before executing your clear contents.
For your second question, you should probably ask about it in a separate post.

Answer 2

A Worksheet Change
Adjust the table name (tName) and the header (column) name (hName).
I have adjusted it to clear contents in the cells after the column.
If you really need to clear the contents of the column too, then replace cel.Offset(, 1) with cel.
In a table, the current setup will automatically clear the contents of all the cells to the right of the specified column, if a value in the column is manually or via VBA changed. This will not work if the column contains formulas. Non-contiguous deletions are also supported.
The code
Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
Const ProcName As String = "Worksheet_Change"
On Error GoTo clearError
Const tName As String = "A_"
Const hName As String = "OPERATION"
Dim rng As Range
Set rng = Range(tName & "[" & hName & "]")
Set rng = Intersect(rng, Target)
If rng Is Nothing Then GoTo ProcExit
Application.EnableEvents = False
With ListObjects(tName).HeaderRowRange
Dim LastColumn As Long
LastColumn = .Columns(.Columns.Count).Column
End With
Dim cel As Range
For Each rng In rng.Areas
For Each cel In rng.Cells
With cel.Offset(, 1)
.Resize(, LastColumn - .Column + 1).ClearContents
End With
Next cel
Next rng
CleanExit:
Application.EnableEvents = True
GoTo ProcExit
clearError:
Debug.Print "'" & ProcName & "': " & vbLf _
& " " & "Run-time error '" & Err.Number & "':" & vbLf _
& " " & Err.Description
On Error GoTo 0
GoTo CleanExit
ProcExit:
End Sub

Answer 3

A change in cell value is captured by the Worksheet_Change event-handle.
However, this handle will trigger even if it is a false change. For example, if the cell value before the change is "A", and user just entered "A" again in the cell, the Change event procedure will be triggered anyhow.
To avoid this, we can use Worksheet_Change and Worksheet_SelectionChange together.
Using Worksheet_SelectionChange, we record the old value somewhere, say a Name. Then using Worksheet_Change, we can compare what the user has entered against the Name to see if a true change is made.
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim Nm As Name: Set Nm = ActiveWorkbook.Names("OldValue")
If Target.Count = 1 Then
'This only record one old cell value.
'To record multiple cells old value, use a hidden Worksheet to do so instead of a Name.
Nm.Comment = Target.Value2
else
Nm.Comment = Target.Value2(1, 1)
End If
End Sub
Private Sub Worksheet_Change(ByVal Target As Range)
Dim Nm As Name: Set Nm = ActiveWorkbook.Names("OldValue")
If Target.Value2 <> Nm.Comment Then
Debug.Print "True change"
Else
Debug.Print "False change"
End If
End Sub
You can access a table's methods and properties through the listobject object. Below is an example how to do so.
Sub Example()
Dim lo As ListObject
Dim lc As ListColumn
Set lo = Range("Table1").ListObject
Set lc = lo.ListColumns("Column2")
End Sub
That said, for your case, it would be Range("A_").ListObject.ListColumns("OPERATION").DataBodyRange.