c# – 来自TPH继承中的子类型的LINQ .Include()属性

我怎样才能做到这一点？

public class Department
{
    public Department()
    {
        DepartmentType = this.GetType.Name;
    }
    public int Id {get; set;}
    public string DepartmentType {get; set;}
}

public class Finance : Department
{
    public virtual Manager Manager {get; set;}
}

public class Sports : Department
{
    public virtual Coach Coach {get; set;}
}


// This obviously crashes instantly
// How can I include Manager if type is Finance and Coach if type is Sports?
context.Departments
        .Include(c => (c is Finance) ? c.Manager : null)
        .Include(c => (c is Sports) ? c.Coach : null);

我甚至试图返回IEnumerable< object>并为每个子类型添加一个多态方法,如下所示：

public class Sports : Department
{
    public Coach Coach {get; set;}

    public object Export()
    {
        return new 
        {
            this.Id,this.DepartmentType,this.Coach
        }
    }
}

然后做这样的事情：

context.Departments.Select(c => c.Export())

但这也不起作用.

期望的JSON用法

[
    { Id: 1,DepartmentType: "Finance",Manager: { Name: "John" } },{ Id: 2,Manager: { Name: "Harold" } },{ Id: 3,DepartmentType: "Sport",Coach: { Name: "Fred",SportType: "Soccer" } },{ Id: 4,Manager: { Name: "Hank" } },{ Id: 5,Coach: { Name: "Mark",SportType: "Football" } }
]