Question

我正在尝试重构一个从DB中提取一些QuerySuggest类型的对象的类。使用Linq对数据库返回的对象进行两次查询。

很明显，这两个查询几乎相同，唯一的区别是前者我有一个附加条件：“＆amp;＆amp; e.UserId == request.UserId”。

在我看来这是一种代码味道，我想重构它，但我不确定如何继续。

这是我需要重构的代码示例：

IRepository<QuerySuggest> repository = _repositoryManager.GetRepository<QuerySuggest>(_repositoryType);

        //entitiesByUser contains all the query suggest by the user
        var entitiesByUser = repository.Query(c => c.Where(e => e.IdWebsite == request.WebSiteId &&
                                                        e.FulltextFree != null &&
                                                        e.DataOra >= (System.DateTime.Today.AddDays(-60).Date) &&
                                                        e.UserId == request.UserId)
                                                .GroupBy(g => g.FulltextFree)
                                                .Select(n => new { FulltextFree = n.Key, HowMany = n.Count() })
                                                .Where(w => w.HowMany >= request.HowMany)
                                                .OrderBy(o => o.HowMany))
                                                .ToList();
        //entitiesByUser contains all the query suggest not from user
        var nonUserEntities = repository.Query(c => c.Where(e => e.IdWebsite == request.WebSiteId &&
                                                        e.FulltextFree != null &&
                                                        e.DataOra >= (System.DateTime.Today.AddDays(-60).Date))
                                                .GroupBy(g => g.FulltextFree)
                                                .Select(n => new { FulltextFree = n.Key, HowMany = n.Count() })
                                                .Where(w => w.HowMany >= request.HowMany)
                                                .OrderBy(o => o.HowMany))
                                                .ToList();

Answer 1

我认为这应该是一种方法：

EphemeralKeyRing

Answer 2

您可以编写一个结合谓词的方法。 @Jon Skeet在这里提供了两种方法：

Combine Multiple Predicates

你应该可以使用这样的东西：

Predicate<YourType> a = e => e.IdWebsite == request.WebSiteId &&
                                            e.FulltextFree != null &&
                                            e.DataOra >= (System.DateTime.Today.AddDays(-60).Date);

Predicate<YourType> b = e => e.UserId == request.UserId;

var entitiesByUser = repository.Query(c => c.Where(Helpers.And(a, b)));

从两个几乎相同的Linq查询中提取方法

2 个答案: