ASP.NET

    <asp:CollapsiblePanelExtender ID="collapsibleSkills" runat="server" Collapsed="False" TargetControlID="panelSkills" CollapseControlID="lblSkills" ExpandControlID="lblSkills" CollapsedText="[+] Skills :" ExpandedText="[-] Skills :" TextLabelID="lblSkills" />
    <br /><dxe:ASPxLabel ID="lblSkills" runat="server" Text="Skills :" Font-Bold="true" Font-Size="Large" /><br />
    <asp:Panel ID="panelSkills" runat="server">
        <ul id="Ul1" runat="server">
            <li>Project Management using different project management software.</li>
            <li>ITIL v3 Foundation.</li>
        </ul>
        <hr />
    </asp:Panel>
</pre>

private Dictionary<Guid, string> Names
        {
            get { return (Dictionary<Guid, string>)ViewState["Names"]; }
            set
            {
                ViewState["Names"] = value;
            }
        }

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                /*
                 * to keep this sample really simple, we will populate some
                 * sample data in a Dictionary and store in the viewstate
                */
                var names = new Dictionary<Guid, string>
                            {
                                {Guid.NewGuid(), "John"},
                                {Guid.NewGuid(), "Smith"},
                                {Guid.NewGuid(), "Arther"},
                                {Guid.NewGuid(), "Hari"}
                            };
                //store the list in the viewstate.
                ViewState.Add("Names", names);
            }
        }

      
        protected void btnAddSave_Click(object sender, EventArgs e)
        {
            if (Page.IsValid)
            {
                Names.Add(Guid.NewGuid(), txtNewName.Text);
                
            }
        }