FONCTION ISNUMERIC AMÉLIORÉE

Private Function IsDouble(ByRef Chaine As String) As Boolean
Dim i As Integer
Dim digit As Integer
Dim char As String * 1
Dim Point As Boolean
IsDouble = True
Point = False
For i = 1 To Len(Chaine)
    char = Mid(Chaine, i, 1)
    digit = Asc(char)
    If (i <> 1) Or ((i = 1) And char <> "-") Then
        If digit <> 46 And (digit < 48 Or digit > 57) Then
            IsDouble = False
            Exit Function
        Else
            If (digit = 46) Then
                If Point = True Then
                    IsDouble = False
                Else
                    Point = True
                End If
            End If
        End If
    Else
        If Len(Chaine) <= 1 Then
            IsDouble = False
            Exit Function
        End If
    End If
Next i
End Function