If Not Application.Dialogs(xlDialogOpen).Show Then Exit Sub
Sub ImporterFeuilles()
Dim wBase As Workbook, wOuvert As Workbook, WS As Worksheet
Set wBase = ThisWorkbook
If Not Application.Dialogs(xlDialogOpen).Show Then Exit Sub
Set wOuvert = ActiveWorkbook
For Each WS In wOuvert.Worksheets
WS.Copy After:=wBase.Worksheets(wBase.Worksheets.Count)
Next WS
End Sub
wOuvert.Close False