private ExamSuitContext GetCachedESContext(string userId) { ContextInfo ci = cManager.GetAndRemoveESContext(userId); if (ci == null) { return(null); } DateTime currentTime = DateTime.Now; if (currentTime.Subtract(ci.lastUpdatedTime).TotalMinutes > 480) //8 hours { return(null); } else { ExamSuitContext esContext = JsonConvert.DeserializeObject <ExamSuitContext>(ci.jsonString); return(esContext); } }