Server Error in '/' Application.

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 107:        pagenum = "select count(id)as nums from info as a where a.cid in(" + classids + ") " + parameters;
Line 108:        OleDbDataReader dr = con.DrSelect(pagenum, null);
Line 109:        if (dr.Read())
Line 110:        {
Line 111:            pagenum = dr["nums"].ToString();

Source File: f:\netweb\hl_netweb\news.aspx.cs    Line: 109

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
   news.Pageing(String pagecount, String pagecurrent, String classId, String pageurl, String sortstr, String parameters) in f:\netweb\hl_netweb\news.aspx.cs:109
   news.Page_Load(Object sender, EventArgs e) in f:\netweb\hl_netweb\news.aspx.cs:82
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +50
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627

Version Information: Microsoft .NET Framework Version:2.0.50727.3053; ASP.NET Version:2.0.50727.3053