if (this.unitOfWork == null)
                if (this.Session["Login"] == null || this.Session["Password"] == null)
                    this.unitOfWork = new UnitOfWork(ConfigurationManager.AppSettings["dbServer"],
                                                     ConfigurationManager.AppSettings["dbName"]);
                else
                    this.unitOfWork = new UnitOfWork(ConfigurationManager.AppSettings["dbServer"],
                                                     ConfigurationManager.AppSettings["dbName"],
                                                     (string)this.Session["Login"], (string)this.Session["Password"]);