Dim x As Range
With Sheets("Feuil1")
Set x = Sheets("Feuil1").Cells.Find(Modif.TextBox1.Value, , xlValues, xlWhole, , , False)
If x Is Nothing Then
MsgBox ("Ce projet n'existe pas")
Else
Worksheets("Feuil1").Select
Cells(1, x) = Modif.TextBox2.Value
End If
End With