public void UpdateChat(EncryptedChatWaitingConstructor chat, byte[] a) { Deployment.Current.Dispatcher.BeginInvoke(() => { var echats = from dialog in session.Dialogs.Model.Dialogs where dialog is DialogModelEncrypted && ((DialogModelEncrypted)dialog).Id == chat.id select dialog; if (echats.Any()) { // ??? } else { session.Dialogs.Model.Dialogs.Insert(0, new DialogModelEncrypted(session, chat, a)); } }); }