自定义服务器控件的取值

ServerContrl1.cs的代码using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;namespace ServerControl1
{
    [DefaultProperty("CurrentPage")]
    [ToolboxData("<{0}:ServerControl1 runat=server></{0}:ServerControl1>")]
    public class ServerControl1 : WebControl, IPostBackEventHandler
    {
        #region 当前页码
        [Description("当前选择页码")]
        [Bindable(true)]
        [Category("Appearance")]
        [DefaultValue(1)]
        public int CurrentPage
        {
            get
            {
                String ss = Convert.ToString(ViewState["CurrentPage"]);
                int nn = 0;
                int.TryParse(ss, out nn);
                return (nn <= 0) ? 1 : nn;
            }
            set
            {
                if (value <= 0)
                {
                    ViewState["CurrentPage"] = 1;
                }
                else
                {
                    ViewState["CurrentPage"] = value;
                }
            }
        }
        #endregion        public delegate void PageChangeEventHandler(object sender, EventArgs e);
        public event PageChangeEventHandler ChangePageClick;
        public void RaisePostBackEvent(string eventArgument)
        {
            int PageIndex = int.Parse(eventArgument);
            this.CurrentPage = PageIndex;
            OnPageChangeClick(new EventArgs());
        }        protected virtual void OnPageChangeClick(EventArgs e)
        {
            if (ChangePageClick != null)
            {
                ChangePageClick(this, e);
            }
        }        protected override void RenderContents(HtmlTextWriter output)
        {
            StringBuilder Str = new StringBuilder();
            Str.Append("当前："+CurrentPage.ToString());
            Str.Append(" <a id=\"" + this.UniqueID + "\" title='' href=\"javascript:" + Page.GetPostBackEventReference(this, (CurrentPage - 1).ToString()) + "\">上一页</a>");
            Str.Append(" <a id=\"" + this.UniqueID + "\" title='' href=\"javascript:" + Page.GetPostBackEventReference(this, (CurrentPage + 1).ToString()) + "\">下一页</a>");
            output.Write(Str.ToString());
        }
    }
}
调用页default.aspx 的      <%=ServerControl11.CurrentPage%>
        <br />
        <cc1:ServerControl1 ID="ServerControl11" runat="server" />这个显示是对的。即<%=ServerControl11.CurrentPage%>和当前的页面值相同
而 default.cs 中 Response.Write(this.ServerControl11.CurrentPage); 却比当前的页面值晚一步。
请教大侠如何解决才能在 default.cs中同步显示