Private Sub CommandButton1_Click()
Sheets("Feuil1").Select
Dim Valeur As Integer
For Valeur = 1 To 1000
On Error GoTo GestionsDesErreurs
myVar = Application.WorksheetFunction _
.Match(Valeur, Worksheets(ActiveSheet.Name).Range("A1:A1000"), 0)
On Error GoTo 0
Next
GestionsDesErreurs:
If Err = 1004 Then
Err = 0
M1 = Valeur
End If
Exit Sub
End Sub