Select multiple nested levels of child tables in Entity Framework Core
I want to get multiple nested levels of child tables in Entity Framework Core using eager loading. I don't think lazy loading is implemented yet.
I found an answer for 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);
My problem is that Select
is not recognized in EF Core
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?)
My included namespaces:
using MyProject.Models;
using Microsoft.Data.Entity;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
What is the alternative for Select
in EF Core.
You can use the keyword ThenInclude
instead
e.g.
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);
Also, the .ThenInclude intellisense for only works up to the 3rd level, for example:
_Context.A.Include(a => a.B).ThenInclude(B => B.C).ThenInclude(C => C.D)
The last part of that statement:
.ThenInclude(C => C.D)
won't show "D", so you have to type D in yourself, then wait for a short period of time for the compilation error to disappear!