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POWhy does session object throw a null reference exception?
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copied!<p>on some of my aspx page I am checking session like this</p> <pre><code>if (bool.Parse(Session["YourAssessment"].ToString()) == false && bool.Parse(Session["MyAssessment"].ToString()) == true) { Response.Redirect("~/myAssessment.aspx"); } </code></pre> <p>It works fine if I keep playing with the pages frequently, but if I don't do anything with the page at least even for 5 min, running the page throws the error </p> <pre><code>Object reference not set to an instance of an object. </code></pre> <p>Following is the stack for this</p> <pre><code>[NullReferenceException: Object reference not set to an instance of an object.] yourAssessment.Page_Load(Object sender, EventArgs e) in d:\Projects\NexLev\yourAssessment.aspx.cs:27 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) +91 System.Web.UI.Control.LoadRecursive() +74 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2207 </code></pre> <p>Could some body explain me this weird behaviour?</p> <p>And as we know by default the session last for is 20 min.</p> <p>EDITED</p> <p>See I have a page default aspx, it has got a button which fixes on the some basis where to redirect On default page it check like this</p> <pre><code>protected void Page_Load(object sender, EventArgs e) { if (!HttpContext.Current.Request.IsAuthenticated) { Response.Redirect("~/login.aspx"); } else { Session["YourAssessment"] = false; Session["MyAssessment"] = false; } } </code></pre> <p>on button click it has</p> <pre><code>protected void imgClientFreeEval_Click(object sender, System.Web.UI.ImageClickEventArgs e) { if (HttpContext.Current.Request.IsAuthenticated) { string sqlQuery = "SELECT count(*) FROM SurveyClient WHERE UserID='" + cWebUtil.GetCurrentUserID().ToString() + "'"; SqlParameter[] arrParams = new SqlParameter[0]; int countSurvey = int.Parse( Data.GetSQLScalerVarQueryResults(sqlQuery).ToString()); if (countSurvey > 0) { Session["YourAssessment"] = true; Session["MyAssessment"] = false; } Response.Redirect((countSurvey > 0) ? "~/yourAssessment.aspx" : "~/myAssessment.aspx"); } else { Response.Redirect("~/login.aspx"); } </code></pre> <p>and on myAssessment page it check like this</p> <pre><code>protected void Page_Load(object sender, EventArgs e) { if (!HttpContext.Current.Request.IsAuthenticated) { Response.Redirect("~/login.aspx"); } else { if (Session["YourAssessment"] != null && Session["MyAssessment"] != null && bool.Parse(Session["YourAssessment"].ToString()) && !bool.Parse(Session["myAssessment"].ToString())) { Response.Redirect("~/yourAssessment.aspx"); } } } </code></pre> <p>and on yourAssessmtn it check like this</p> <pre><code>protected void Page_Load(object sender, EventArgs e) { if (!HttpContext.Current.Request.IsAuthenticated) { Response.Redirect("~/login.aspx"); } else { if (Session["YourAssessment"] != null && Session["MyAssessment"] != null && !bool.Parse(Session["YourAssessment"].ToString()) && bool.Parse(Session["MyAssessment"].ToString())) { Response.Redirect("~/myAssessment.aspx"); } PopulateAllSurveyByUser(); if (ViewState["surveyClientID"] != null) { grdSurveyDetail.Visible = true; PopulateSurveyDetails( int.Parse(ViewState["surveyClientID"].ToString())); } else { grdSurveyDetail.Visible = false; } } } </code></pre> <p>what's wrong please explain?</p>

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