public MainPageViewModel(IChatClient chatClient) { _chatClient = chatClient; SendMessageCommand = Text.Select(s => !string.IsNullOrEmpty(s)).ToAsyncReactiveCommand(); SendMessageCommand.Subscribe(async() => { var text = Text.Value; Text.Value = null; await _chatClient.CreateMessageAsync("0", text, UserId); }); _chatClient.ObserveMessageCreated("0") .Subscribe((message) => Messages.Add(message)) .AddTo(_disposable); }