Question

Private Sub Worksheet_Change(ByVal Target As Range)
Dim r1 As Range
Set r1 = Range("A1:B10")
If Intersect(Selection, r1) Is Nothing Then Exit Sub  ' how to write this line ?
MsgBox "323"
End Sub

I want the MsgBox only if I manually select and change some cell inside r1, not by running another code which changes this cells.

Answer 1

Try this

In a Module, declare a Public variable

Public CodeChangingCells As Boolean

In all you Subs that can change relavent cells set this variable

Sub SubTahtChangesCells()

On Error GoTo EH

CodeChangingCells = True
Sheet1.[A1] = Sheet1.[A1] + 1

CleanUp:
On Error Resume Next
CodeChangingCells = False
Exit Sub
EH:
  ' Handle errors

GoTo CleanUp
End Sub

Test this variable in the Cnage event
Use Target rather than Selection

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim r1 As Range
    If Not CodeChangingCells Then
        Set r1 = Me.Range("A1:B10")
        If Intersect(Target, r1) Is Nothing Then Exit Sub  ' how to write this line ?
        MsgBox "323"
    End If
End Sub