RX 最佳实践:选择有副作用或使用订阅

我将事件（来自按钮的分页事件）转换为IObservable，并从服务异步接收结果。

作为副作用，我必须更新子视图。我有两个解决方案：

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. 在订阅中做副作用：

       //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());
       });
   

这两种方法都有效。我应该选择哪种解决方案，为什么？

感谢。

因为存在为什么这会产生值的问题，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;
            }
        });

它的实际作用是在搜索字符串更改时向数据库发送搜索请求并获得分页结果，或者在收到 PageChangedEvent 时获取具有相同搜索字符串的另一个页面。是否 .合并（...）订阅？