Master page 取得 子頁面的元件 VB.NET

   Dim abc As String
        
'P3 為 USERMTAControl

先從ContentPlaceHolder1找到P3
再由P3去取得旗下元件

        Dim P3 As UserControl = DirectCast(ContentPlaceHolder1.FindControl("P3"), UserControl)



        abc = CType(P3.FindControl("Labelaaaa1"), Label).Text
        Response.Write("<script>alert('" + abc + "');</script>")