I have Ext:Store defined in aspx page. and on page_load I assign datasource to it and bind to datasource. I steped in the code and make sure there is data in datasource. but in the client side I cannot get data in the store. Can you take a look at the code if there are anyting wrong?

Server side code in Page_Onload:
               DataTable dt = new DataTable();
                dt.Columns.Add(new DataColumn("PageID", typeof(int)));
                dt.Columns.Add(new DataColumn("PageUrl", typeof(string)));
                dt.Columns.Add(new DataColumn("FileName", typeof(string)));
                dt.Columns.Add(new DataColumn("BatchNumber", typeof(string)));
                dt.Columns.Add(new DataColumn("IsDocumented", typeof(bool)));
                dt.Columns.Add(new DataColumn("CreatedDate", typeof(DateTime)));
                dt.Columns.Add(new DataColumn("PageCount", typeof(int)));
                dt.Columns.Add(new DataColumn("FileExt", typeof(string)));
                dt.Columns.Add(new DataColumn("CreatedBy", typeof(string)));
                dt.Columns.Add(new DataColumn("DocumentBy", typeof(string)));

                dt.AcceptChanges();

                List<PagesWrapper> showPages = PagesWrapper.FindAllByDocIDandTypeNoLock(GetDocumentID(), GetFileType());

                if (showPages.Count > 0)
                {
                    initPageID = showPages[0].PageID;
                }
                int pageid = 0;
                foreach (PagesWrapper page in showPages)
                {
                    //BindPagerInfo(page);
                                        
                    DataRow dr = dt.NewRow();
                    dr["PageID"] = page.PageID;
                    dr["PageUrl"] = "";
                    dr["FileName"] = page.FileName;
                    dr["BatchNumber"] = page.BatchNumber;
                    dr["IsDocumented"] = page.IsDocumented;
                    dr["CreatedDate"] = page.CreatedDate;
                    dr["FileExt"] = page.FileExt;
                    dr["CreatedBy"] = page.DisplayCreateBy;
                    dr["DocumentBy"] = page.DisplayDocumentedBy;
                    if (page.PageCount == null && page.PageCount == 0)
                    {
                        try
                        {
                            dr["PageCount"] = DocumentsWrapper.CalculatePageSize(page.FileExt, page.GetFileContent(), DotImageDocumentProcessor.GetDocumentProcessor());
                        }
                        catch (Exception ex)
                        {
                            dr["PageCount"] = 1;
                        }
                    }
                    else
                    {
                        dr["PageCount"] = page.PageCount;
                    }

                    dt.Rows.Add(dr);
                    //}
                }

                dt.AcceptChanges();

                storePageData.DataSource = dt;
                storePageData.DataBind();
on client side page code:
<ext:Store ID="storePageData" runat="server">
       <Model>
             <ext:Model runat="server" IDProperty="PageID">
                  <Fields>
                       <ext:ModelField Name="PageID" Type="Int"/>
                       <ext:ModelField Name="PageUrl" Type="String" />
                       <ext:ModelField Name="FileName" Type="String" />
                       <ext:ModelField Name="BatchNumber" Type="String" />
                       <ext:ModelField Name="IsDocumented" Type="Int" />
                       <ext:ModelField Name="CreatedDate" Type="Date" DateFormat="M/d hh:mmtt" />
                       <ext:ModelField Name="PageCount" Type="Int" />
                       <ext:ModelField Name="FileExt" Type="String" />
                       <ext:ModelField Name="CreatedBy" Type="String" />
                       <ext:ModelField Name="DocumentBy" Type="String" />
                   </Fields>
               </ext:Model>
          </Model>           
        <Parameters>
            <ext:StoreParameter Name="pageid" Mode="Raw" Value="document.getElementById('pageid').value">
            </ext:StoreParameter>
        </Parameters>
    </ext:Store>
client side java script code, I debug into code App.storePageData.getCount(); get 0, even it has data bind in page_load. and return App.storePageData.getById(pagerID); returned null value. 

          function GetCurrentPage() {
            var pagerID = document.getElementById("pageid").value;
           var count = App.storePageData.getCount();
            return App.storePageData.getById(pagerID);
        }