在excel中怎么用vba设置标题?

Private Sub CommandButton1_Click()
If ActiveSheet.PageSetup.CenterHeader = "" Then
年级 = Sheets(1).[b3]
ActiveSheet.PageSetup.LeftHeader = "&B" & 年级
ActiveSheet.PageSetup.CenterHeader = "&B " & 年级
CommandButton1.Caption = "取消页眉"
Else
ActiveSheet.PageSetup.CenterHeader = ""
ActiveSheet.PageSetup.LeftHeader = ""
CommandButton1.Caption = "添加页眉"
End If
End Sub