how to retain the state of datagrid page....

protected void GridViewIndexChanging(object sender, GridViewPageEventArgs e)
    {
        myGridView.PageIndex = e.NewPageIndex;
        Session["pageNumber"] = e.NewPageIndex;
        //whatever your page index changing does...
    }

if (!IsPostBack)
     {
         if (Session["pageNumber"] != null)
         {
             GridViewIndexChanged(myGridView, new GridViewPageEventArgs((int)Session["pageNumber"]));
         }
     }