RX最佳做法：选择具有副作用还是使用订阅？

Question

我将事件（按钮的分页事件）转换为IObservable，并异步接收来自服务的结果。

作为副作用，我必须更新子视图。我有两种解决方案：

1. 选择中的副作用：

       //Converting events to a "stream" of search results.
       IObservable<SearchResult> resultsFromPageChange = Observable.FromEventPattern<EventArgs>(this,
           "PageChangedEvent")
           .Throttle(TimeSpan.FromMilliseconds(500))
           .Select(async ev =>
            {
                var input = new SearchResultInput()
                {
                    PageSize = PageSize,
                    PageIndex = PageIndex,
                    SearchOptions = _currentSearchOptions,
                    SearchText = SearchText.Value
                };
                var result = await GetPagedComponents(input);
                //Side effect
                ActivateAttributesView(result.Components.FirstOrDefault());
   
                return result;
            }).Switch(); //flatten and take most recent.
   

2. 在subsribe中做副作用：

       //Converting events to a "stream" of search results.
       IObservable<SearchResult> resultsFromPageChange = Observable.FromEventPattern<EventArgs>(this,
           "PageChangedEvent")
           .Throttle(TimeSpan.FromMilliseconds(500))
           .Select(async ev =>
           {
               var input = new SearchResultInput()
               {
                   PageSize = PageSize,
                   PageIndex = PageIndex,
                   SearchOptions = _currentSearchOptions,
                   SearchText = SearchText.Value
               };
               return await GetPagedComponents(input);
           }).Switch(); //flatten and take most recent.
   
       //Do side effect in the subscribe
       resultsFromPageChange.Subscribe(x =>
       {
           if (x != null)
               ActivateAttributesView(x.Components.FirstOrDefault());
       });
   

两种方法都有效。我应该选择哪种解决方案，为什么？

谢谢。

因为有一个疑问，为什么它根本不能产生值，所以下面是完整的代码：

        //Converting events to a "stream" of search results.
        IObservable<SearchResult> resultsFromPageChange = Observable.FromEventPattern<EventArgs>(this,
            "PageChangedEvent")
            .Throttle(TimeSpan.FromMilliseconds(500))
            .Select(async ev =>
            {

                var input = new SearchResultInput()
                {
                    PageSize = PageSize,
                    PageIndex = PageIndex,
                    SearchOptions = _currentSearchOptions,
                    SearchString = SearchString.Value
                };

                return await SearchComponentsPaged(input);

            }).Switch(); //flatten and take most recent.

        SearchString = new ReactiveProperty<string>(""); //Bound to TextBox.Text 

        //Create a "stream" of search results from a string given by user (SearchString)
        SearchResult = SearchString
            .SetValidateNotifyError(s => _componentDataService.ValidateSearchStringLength(s).Errors)
            .Throttle(TimeSpan.FromMilliseconds(500))
            .Select(async term =>
            {
                var input = new SearchResultInput()
                    {
                        PageSize = PageSize,
                        PageIndex = PageIndex,
                        SearchOptions = _currentSearchOptions,
                        SearchString = term
                    };

                return await SearchComponentsPaged(input);

            })
            .Switch()
            .Merge(resultsFromPageChange) //Merge the result of paging and text changing.  
            .ToReactiveProperty();

        //Update Attributes view
        SearchResult.Subscribe(searchResult =>
        {
            if (searchResult != null)
            {
                ActivateAttributesView(searchResult.Components.FirstOrDefault());
                SearchResult.Value.TotalItemsCount = searchResult.TotalItemsCount;
            }

        });

它的实际作用是，当搜索字符串更改并获取分页结果时，向数据库发送搜索请求，或者在收到PageChangedEvent时使用相同的搜索字符串获取另一个页面。.Merge（...）是否订阅？

Answer 1

我会考虑您的第二个解决方案。由于不同的订户可以选择具有不同的副作用，因此它更加灵活。它还分离了关注点，Rx查询生成数据，订阅者根据需要使用数据。