用户控件更改属性和使用在usercontrol的代码后面

我有一个从一个母版页继承的aspx页面，并有两个内容占位符，像这样:

   <%@ Register Src="Controls/YearBook/YearBookExpander.ascx" TagName="YearBookExpander" TagPrefix="uc1" %>
<%@ Register Src="Controls/YearBook/YearBook.ascx" TagName="YearBook" TagPrefix="uc2" %>
<%@ Register Src="Controls/YearBook/YearBookSearch.ascx" TagName="YearBookSearch" TagPrefix="uc3" %>
<asp:Content ID="Content1" ContentPlaceHolderID="cphHead" runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="cphMenu" runat="Server">
    <asp:UpdatePanel ID="upExpander" runat="server" UpdateMode="Conditional">
        <ContentTemplate>
            <nav id='main-nav'>
            <asp:Panel ID="pnlExpander" runat="server" CssClass="navigation">
                <uc1:YearBookExpander ID="ybExpander" runat="server" OnSearchClickEvent="ybExpander_Search" />
            </asp:Panel>
            </nav>
        </ContentTemplate>
    </asp:UpdatePanel>
</asp:Content>
<asp:Content ID="Content3" ContentPlaceHolderID="cphPage" runat="Server">
    <asp:Panel ID="pnlPage" runat="server">
        <uc2:YearBook ID="YearBook1" runat="server" ContentVisible="true" />
        <uc3:YearBookSearch ID="ybSearch" runat="server" />
    </asp:Panel>
</asp:Content>
<asp:Content ID="Content4" ContentPlaceHolderID="cphScripts" runat="Server">
    <script src="../Scripts/PersianCalendar.js" type="text/javascript"></script>
    <script type="text/javascript">
        Calendar = 1;
    </script>
</asp:Content>

一些javascript的原因，我不能把我的"cphPage"内容到更新面板，我需要显示/取消显示cphPage的用户控制的基础上链接点击在cphMenu。为此，我将面板添加到usercontrol的更新面板中，并希望在post back发生时显示或不显示此面板，因此我在每个用户控件中定义一个属性(在cphPage内容占位符中):

[Bindable(true, BindingDirection.TwoWay)]
    public bool ContentVisible
    {
        get { return Convert.ToBoolean(Session["ContentVisible"]); }
        set { Session["ContentVisible"] = value; }
    }

和在aspx代码后面更改值基础一次点击链接:

private void uExpander_ExpanderClicked(object sender, ExpanderEventArgs e)
{
    switch (e.Clicked)
    {
        case "YearBook":
            YearBook1.ContentVisible = true;
            ybSearch.ContentVisible = false;
            break;
        case "Search":
            ybSearch.ContentVisible = true;
            YearBook1.ContentVisible = false;
            break;
        default:
            YearBook1.ContentVisible = true;
            ybSearch.ContentVisible = false;
            break;
    }
}

和在用户控件，我检查这个值可见/不可见的usercontrol的面板:

if (ContentVisible)
        {
            pnlCalendar.Visible = true;
            pnlDefaultEvents.Visible = true;
            pnlAddEvent.Visible = true;
        }
        else
        {
            pnlCalendar.Visible = false;
            pnlDefaultEvents.Visible = false;
            pnlAddEvent.Visible = false;
        }

但是这段代码不会工作，因为用户控件在执行aspx代码之前启动…我该如何实现这个场景?还有其他的解决方案吗?

thank you