Sub MasquerAfficher()
Dim ncolonne&
With ActiveSheet
.Rows(1).EntireColumn.Hidden = False
If CmB_Jour = "" Then Exit Sub
ncolonne = Application.WorksheetFunction.Match(CLng(CDate(CmB_Jour)), .Rows(2), 0)
If ncolonne > 4 Then .Range(.Cells(1, "d"), .Cells(1, ncolonne - 1)).EntireColumn.Hidden = True
End With
End Sub