c# - 按 Entity Framework 中的子集合排序

Question

我有一个如下所示的 Entity Framework 模型:

public class User
{
  public DateTime DateCreated {get;set;}
  publc virtual List<Car> Cars {get;set;}
}

public class Car
{
  public string ModelType {get;set;}
}

现在我想获取所有用户，并按 DESC 排序，以便拥有 ModelType 为“Sedan”的汽车的用户位于顶部。

在我的查询中，我通过包含属性“Cars”进行一些预加载，但我不确定如何为子属性排序。

我正在使用基于此的通用存储库模式:http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/implementing-the-repository-and-unit-of-work-patterns-in-an-asp-net-mvc-application

目前我的方法是这样的:

    public List<User> GetUsers()
    {
        return Get(orderBy: o => o.OrderByDescending(u => u.DateCreated), 
            includeProperties: "Cars").ToList();
    }

所以它有一个 Get 方法，如下所示:

public virtual IEnumerable<TEntity> Get(
            Expression<Func<TEntity, bool>> filter = null,
            Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
            string includeProperties = "")
        {
            IQueryable<TEntity> query = dbSet;

            if (filter != null)
            {
                query = query.Where(filter);
            }

            foreach (var includeProperty in includeProperties.Split
                (new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
            {
                query = query.Include(includeProperty);
            }

            if (orderBy != null)
            {
                return orderBy(query).ToList();
            }
            else
            {
                return query.ToList();
            }
        }

Answer 1

想法是

OrderByDescending(u => u.Cars.Any(c => c.ModelType == "Sedan"));

(有点怀疑boolean，我觉得应该是OrderByDescending，但是……我让你查一下。)