一个包含后如何执行多个ThenInclude导航道具

问题描述

对于TestType，我想同时包含导航道具Schoolclass和Subject。

For a TestType I wanted to include both navigation props Schoolclass and Subject.

我可以这样做：

.Include(t => t.TestType)
 .ThenInclude(x => x.Subject)

但不是a：

.Include(t => t.TestType)
.ThenInclude(x => x.Subject)
.ThenInclude(x => x.Schoolclass)

因此，我尝试了一些技巧，并成功了：

Thus I tried a little trick and that worked:

我将TestType包含了2次...

I included the TestType 2 times...

var test = await context.Tests.Where(t => t.SchoolyearId == schoolyearId)
                                          .Include(t => t.TestType)
                                          .ThenInclude(x => x.Subject)
                                           .Include(t => t.TestType)
                                          .ThenInclude(x => x.Schoolclass)
                                           .AsNoTracking()
                                          .ToListAsync();

是官方方法还是更好的方法？

Is that the official approach or is there a better one?

更新

   public class TestType
    {
        public TestType()
        {
            Tests = new HashSet<Test>();
        }

        public int Id { get; set; }
        public string Name { get; set; }
        public int Weight { get; set; }
        public ISet<Test> Tests { get; set; }
        public Schoolyear Schoolyear { get; set; }  
        public Schoolclass Schoolclass { get; set; }   
        public Subject Subject { get; set; }
        public int SchoolyearId { get; set; }
    }

推荐答案

最好的方法是您之前写过，带有两个.Include（t => t.TestType）

the best way is that you write before, With two .Include(t => t.TestType)

var test = await context.Tests.Where(t => t.SchoolyearId == schoolyearId)
                                      .Include(t => t.TestType)
                                      .ThenInclude(x => x.Subject)
                                       .Include(t => t.TestType)
                                      .ThenInclude(x => x.Schoolclass)
                                       .AsNoTracking()
                                      .ToListAsync();

如果在SQL事件探查器中看到查询结果，则该查询是您假装的，无需重复包含到TestType（只有1个连接到该表）

If you see the query result in SQL Profiler, the query is that you pretend, without repeating the include to TestType (only 1 join with that table)

您还有另一种方法，但是我更喜欢以前的方法！

You have another way to do it, but i prefer the before way!

.Include("TestType.Subject") 
.Include("TestType.Schoolclass")  

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