Set doublon = Sheets("Feuil2").Range("C2:C" & Sheets("Feuil2").Range("C65536").End(xlUp).Row).Find(What:=CDate(TextBox1.Text), LookIn:=xlValues, LookAt:=xlWhole)
If Not doublon Is Nothing Then
Select Case MsgBox("la Date existe déjà la supprimer OUI ou NON ?", vbYesNo)
Case vbYes
Dim l As Long
Sheets("Feuil2").Select
For l = Cells.SpecialCells(xlCellTypeLastCell).Row To 1 Step -1
If Cells(l, 3).Value = TextBox1.Text Then Cells(l, 3).EntireRow.Delete
Next l
Case vbNo
TextBox1 = ""
TextBox1.SetFocus
Exit Sub
End Select
End If