如何在C# web窗体应用程序中保持侧导航栏在回发时隐藏？

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        // 初始化侧导航栏的显示状态
        ViewState["IsSidebarVisible"] = true;
    }
    else
    {
        // 从 ViewState 中读取侧导航栏的显示状态
        bool isSidebarVisible = (bool)ViewState["IsSidebarVisible"];
        sidebarDiv.Visible = isSidebarVisible;
    }
}

protected void ToggleSidebar_Click(object sender, EventArgs e)
{
    // 切换侧导航栏的显示状态
    bool isSidebarVisible = (bool)ViewState["IsSidebarVisible"];
    ViewState["IsSidebarVisible"] = !isSidebarVisible;
    sidebarDiv.Visible = !isSidebarVisible;
}

<div id="sidebarDiv" runat="server" visible="true">
    <!-- 侧导航栏内容 -->
</div>
<button id="ToggleSidebar" runat="server" onserverclick="ToggleSidebar_Click">Toggle Sidebar</button>

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        // 初始化侧导航栏的显示状态
        Session["IsSidebarVisible"] = true;
    }
    else
    {
        // 从 Session 中读取侧导航栏的显示状态
        bool isSidebarVisible = (bool)Session["IsSidebarVisible"];
        sidebarDiv.Visible = isSidebarVisible;
    }
}

protected void ToggleSidebar_Click(object sender, EventArgs e)
{
    // 切换侧导航栏的显示状态
    bool isSidebarVisible = (bool)Session["IsSidebarVisible"];
    Session["IsSidebarVisible"] = !isSidebarVisible;
    sidebarDiv.Visible = !isSidebarVisible;
}

<div id="sidebarDiv" runat="server" visible="true">
    <!-- 侧导航栏内容 -->
</div>
<button id="ToggleSidebar" runat="server" onserverclick="ToggleSidebar_Click">Toggle Sidebar</button>

<div id="sidebarDiv" runat="server">
    <!-- 侧导航栏内容 -->
</div>
<button id="ToggleSidebar" runat="server">Toggle Sidebar</button>

<script type="text/javascript">
    function toggleSidebar() {
        var sidebarDiv = document.getElementById('<%= sidebarDiv.ClientID %>');
        sidebarDiv.style.display = sidebarDiv.style.display === 'none' ? 'block' : 'none';
        // 保存状态到隐藏字段
        document.getElementById('<%= hiddenField.ClientID %>').value = sidebarDiv.style.display;
    }

    window.onload = function() {
        var sidebarDiv = document.getElementById('<%= sidebarDiv.ClientID %>');
        var hiddenField = document.getElementById('<%= hiddenField.ClientID %>');
        if (hiddenField.value) {
            sidebarDiv.style.display = hiddenField.value;
        }
    };
</script>

<asp:HiddenField ID="hiddenField" runat="server" />

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        // 初始化隐藏字段的值
        hiddenField.Value = "block";
    }
}