title: How to persist Asp Net GridView data (coming from SignalR) after page postback?
body: <p>I create module in DotNetNuke CMS. Ihave no need to edit my data, just display 
  with sorting and paging. There is asp:GridView control which has DataTable
  as data source. In Page_Load event some rows with data are added to dataTable and
  properly displayed. Sorting and pagging work ok too. To maintain data in GridView
  (and for sorting purposes) used ViewState. I choosed using of ViewState to not 
  overload the server, incoming data doesn't have to be secure. For incoming data 
  I use SignalR, so javascript function receives data from server(hub).
  Figured out that I will call from javascript web method(C#) AddNewRowToDataTable
  (DateTime time, string name, double value...) passing parameters to the method.
  Unfortunatelly web method must be static and this is the reason why ViewState can 
  not be used in it. So if I can't use ViewState when adding new row I lose all data.
  This doesn't help:</p>
  
  <pre><code>[WebMethod]
  public static void AddNewRowToDataTable(DateTime time, string name, double value)
  {
      Page page = HttpContext.Current.Handler as Page;
      if (page != null)
      {
          if (page.ViewState["dtValues"] != null)
          {
              // Get the DataTable from ViewState and inserting new data to it.
              DataTable dtValues = (DataTable)page.ViewState["dtValues"];
  
              // Add the new row.
              dtValues.Rows.Add(new object[] { time, name, value });
  
              // Rebind the GridView control to show inserted data.
              BindGridView();
          }
      }
  }
  </code></pre>
  
  <blockquote>
    <p>Error Cannot access protected member 'System.Web.UI.Control.ViewState'
    via a qualifier  of type 'System.Web.UI.Page'; the qualifier must be
    of type 'Christoc.Modules.DNNSignalR.View'  (or derived from it)</p>
  </blockquote>
  
  <p>I preferr not to use Session for maintaing data because don't want to heavy load on server side.</p>
  
  <p>What would be the best approach to my requirements: In Asp Net, DotNetNuke module, display data 
  coming from SignalR with sorting and paging functionality, not losing data on postbacks?</p>