Loading Nested Entities / Collections with Entity Framework

Question

I am trying to Eagerly load all the related entities or collection of Entity in one call. My Entities Looks like:

Class Person
{
    public virtual long Id { get; set; }
    public virtual string FirstName { get; set; }
    public virtual string LastName { get; set; }
}

Class Employee
{
    public virtual long Id { get; set; }
    public DateTime AppointmentDate { get; set; }
    public virtual ICollection<EmployeeTitle> Titles { get; set; }
    public virtual Person Person { get; set; }
}

Class EmployeeTitle
{
    public virtual long Id { get; set; }
    public virtual bool IsCurrent { get; set; } 
    public virtual Title Title { get; set; }
}
Class Title
{
    public virtual long Id { get; set; }
    public virtual string Code { get; set; }
    public virtual string Description { get; set; }
}

What Iam trying to do is if i call a method to load all Employees, the result should include Person, List of EmployeeTitles including the code and description from Title I have been able to get to the third level i.e. getting the Employee with person and list of EmployeeTitle. I don't know how to get the title information with the EmployeeTitle. My code to get this is:

Context.Employees.Include("Person").Include(e => e.Titles).ToList();

Please shed some light on how to accomplish this. Thanks in advance.

Slauma · Accepted Answer · 2011-08-04 16:51:20Z

42

You can try this:

Context.Employees
    .Include(e => e.Person)
    .Include(e => e.Titles.Select(t => t.Title))
    .ToList();

Select can be applied to a collection and loads navigation properties of the next level in the object graph.

answered Aug 4, 2011 at 16:51

Slauma

177k60 gold badges407 silver badges424 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Simon_Weaver Over a year ago

IMPORTANT: Don't accidentally use the same variable for both lambda expressions .Include(x => x.Titles.Select(x => x.Title)) or you'll get Cannot convert lambda expression to type 'string' because it is not a delegate type

Torben Junker Kjær Over a year ago

You must have "using System.Data.Entity", otherwise it will appear as this this overload doesn't exist.

Şafak Gür Over a year ago

Is there a way I can achieve this using Include(string)?

Slauma Over a year ago

@ŞafakGür: Yes, just use "dotted paths": Include("Titles.Title")

Matt Borja Over a year ago

+1 Took a while to finally come up with the right keywords in Google ("entity loading related collection that has collections") but this works :)

makuvex · Accepted Answer · 2014-05-08 15:37:28Z

5

Since this is the first page in my search in google, I just wanted to post this.

Slauma's answer is fine. But it's recommended to use Load() instead of ToList() if you don't plan to actually use the list. So it would be:

    Context.Employees
        .Include(e => e.Person)
        .Include(e => e.Titles.Select(t => t.Title))
        .Load();

answered May 8, 2014 at 15:37

makuvex

511 silver badge1 bronze badge

Collectives™ on Stack Overflow

Loading Nested Entities / Collections with Entity Framework

2 Answers 2

5 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related