在加入时包含附加参数

Question

我有很多国家，每个国家我有很多团队。

团队控制器中的 GetTeam 端点检索单个团队及其相关国家。通过 LINQ 查询是这样的：

Context.Teams.Include(t => t.Nation).First(t => t.Id.Equals(__id))

结果JSON就是我想要的：

{"team":{"name":"Team1","nation":{"id":1,"name":"Nation1"}}

现在假设属性 "name"，在团队和国家模型中都被删除，并创建了一个新的模型关系，带有翻译。

我现在想要的是检索相同的 JSON，但使用基于文化的不同查询。开始疯狂了解我如何使用 include 实现它。

如何在 LINQ 中编写此查询？

select * 
from Teams inner join 
Translations TeamTr on Teams.id = TeamTr .id and TeamTr .culture = "IT" inner join 
Nations on Teams.nation_id = Nations.id inner join 
Translations NationTr on Nations .id = NationTr .id and NationTr .culture = "IT"

并按照上面JSON的方式合成结果数据？

Answer 1

例如：

(from team in Context.Teams
join teamTr in Context.Translations on team.id equals teamTr.id
join nation in Context.Nations on team.nation_id equals nations.id
join nationTr in Context.Translations on nation.id equals nationTr.id
where teamTr.culture == "IT" && nationTr.culture == "IT"
select new 
{
   teamName = team.name,
   nationName = nation.name

}).ToList();

Answer 2

今天收获不错。

首先，我创建了一个新的 class，它将作为 linq 结果的容器：

public class TeamDetailLinqDto
{
    public Team Team { get; set; }
    public Translation TeamTranslation { get; set; }
    public Nation Nation { get; set; }
    public Translation NationTranslation { get; set; }
}

这是 linq 查询：

    public IQueryable<TeamDetailLinqDto> GetTeams()
    {
        var result = from team in Context.Teams
                     join teamTranslation in Context.Translations on
                         new { Id = team.Id, Locale = "IT" }
                         equals new { Id = teamTranslation.EntityId, Locale = teamTranslation.Locale }
                     join nation in Context.Nations on team.NationId equals nation.Id
                     join nationTranslation in Context.Translations on
                         new { Id = nation.Id, Locale = "IT" }
                         equals new { Id = nationTranslation.EntityId, Locale = nationTranslation.Locale }
                     select new TeamDetailLinqDto
                     {
                         Team = team,
                         TeamTranslation = teamTranslation,
                         Nation = nation,
                         NationTranslation = nationTranslation
                     };

        return result;
    }

在加入时包含附加参数

Include with additional param on join

linq

entity-framework

ef-core-2.1