XL 2010 Lancer une maccro sur un changement de valeur d'une zone de texte

Private Sub TextBox1_Change()
  MsgBox (1)
Dim i, z As Integer
Dim a As String
Dim sh As Worksheet

i = Sheets.Count
z = 1
'a = Sheets("Page de garde").Shapes("TextBox1").TextFrame.Characters.Text

a = TextBox1.Value
MsgBox (a)
For Each sh In ThisWorkbook.Worksheets
    'If sh.Name <> "Page de garde" Then
        If sh.Name = "Page de garde" Then
           'Sheets(sh.Name).Cells(4, 3) = "FICHE ESSAI LABO N°" & a
           sh.Shapes("ZoneTexte 1").TextFrame.Characters.Text = a
           sh.Shapes("ZoneTexte 1").TextFrame.Characters.Font.Color = RGB(250, 0, 0)
           sh.Shapes("ZoneTexte 1").TextFrame.Characters.Font.Size = 14
           sh.Shapes("ZoneTexte 1").TextFrame.Characters.Font.Name = "Comic Sans MS"
           sh.Shapes("ZoneTexte 1").TextFrame.Characters.Font.Bold = True
           sh.Shapes("ZoneTexte 1").TextFrame.HorizontalAlignment = xlCenter
        End If
   ' End If
    z = z + 1
Next sh
End Sub