Sub Bouton1_Cliquer()
Dim xsh, xcell
For Each xsh In Array("Feuil1", "Feuil2", "Feuil3")
For Each xcell In Array("A2", "B2", "C2")
If Trim(Sheets(xsh).Range(xcell)) = "" Then
MsgBox "il y a au moins un critère vide." & vbLf & _
"Cellule " & Range(xcell).Address(0, 0) & " sur " & xsh, vbCritical
Application.Goto Sheets(xsh).Range(xcell)
Exit Sub
End If
Next xcell, xsh
Sheets("Feuil4").Activate
End Sub