小编Mon*_*ono的帖子

我有一个非常具体的问题.我正在使用android数据绑定库:https: //developer.android.com/topic/libraries/data-binding/index.html

我有这样的数据模型:

Class Participant
Public String Name;
//and so on
Public ObservableArrayList<Drink> DrinkList;
End Class
Class Drink extends BaseObservable
@Bindable
Public String Name;
@Bindable
Public Float Price;
End Class

视图模型:

Class ParticipantList 
public ObservableArrayList<Participant> list = new ObservableArrayList<>();
//some Methods to add items and concstructor

我还为所有@Bindable字段使用Getter和Setter.

现在我有一个带有expandablelistview的活动,我通过XML将一个适配器绑定到expandablelistview,并将自定义的@BindingAdapter绑定到这样:

//in XML for the layout
<layout xmlns:bind="http://schemas.android.com/apk/res-auto"
   <data>
       <variable name="Participants" type="com.example.ParticipantList"/>
   </data>
<ExpandableListview>
<bind:participants=Particpants.list>

在绑定帮助器Class中这个静态方法

    @BindingAdapter("participants")
public static void bindList(ExpandableListView view, ObservableArrayList<Participant> list) {
    ParticipantListAdapter adapter = new ParticipantListAdapter(list);
    view.setAdapter(adapter); …

我有一个问题,我很难找到答案.

我有3个实体类,其关系类似于(简化):

class Article {
 public int id
 public string Name
 public int ArticleStandard Id
 public int CompanyId
 public ArticleStandard ArticleStandardNavigation
 public Company CompanyNavigation
}
class ArticleStandard {
 public int id
 public ICollection<Article> Articles
}
class Company {
 public in id
 public ICollection<Article> Articles
}

所以关系是1公司可以有很多文章,1标准文章可以有很多文章.它们都在DBContext中设置为DBSets.鉴于是ArticleStandard的Id.我现在想通过文章实体获得所有拥有此标准文章的公司.我想"生产"的TSQL是:

  select c.* from Company c
  inner join Article a on c.ID = a.CompanyId
  inner join ArticleStandard on a.ArticleStandard = arts.id
  Where arts.Id = 1

这给出了我想要的结果.

我尝试了很多,我不想发布我的所有试验来解决这个问题,这可以让它与Include和ThenInclude一起工作.但我不想得到所有文章和文章标准.如果我只选择公司,则忽略包含:https: //docs.microsoft.com/en-us/ef/core/querying/related-data#ignored-includes

var vtp = context.Company.Include(a => …