entity-framework-core - 在 Entity Framework Core 中选择多个嵌套级别的子表

Question

我想使用预先加载在 Entity Framework Core 中获得多个嵌套级别的子表。我认为还没有实现延迟加载。

我找到了一个 answer对于 EF6。

var company = context.Companies
                 .Include(co => co.Employees.Select(emp => emp.Employee_Car))
                 .Include(co => co.Employees.Select(emp => emp.Employee_Country))
                 .FirstOrDefault(co => co.companyID == companyID);

我的问题是 Select EF Core 无法识别

Error CS1061 'Employees' does not contain a definition for 'Select' and no extension method 'Select' accepting a first argument of type 'Employees' could be found (are you missing a using directive or an assembly reference?)

我包含的命名空间:

using MyProject.Models;
using Microsoft.Data.Entity;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

Select的替代方案是什么？在 EF Core 中。

Answer 1

您可以使用关键字 ThenInclude反而

例如

var company = context.Companies
             .Include(co => co.Employees).ThenInclude(emp => emp.Employee_Car)
             .Include(co => co.Employees).ThenInclude(emp => emp.Employee_Country)
             .FirstOrDefault(co => co.companyID == companyID);