Entity Framework Include with Func

re: Entity Framework Include with Func

Matthieu MEZIL — Thu, 08 Oct 2009 23:08:28 GMT

I think it's very hard to do it. You should look at this.

re: Entity Framework Include with Func

Nelson — Mon, 05 Oct 2009 15:53:22 GMT

This is really much better, but I'm trying to do something like:

this.Context.Countries.Include(c => c.MetroAreas.OrderBy(m => m.Name)).Include(c => c.Regions.OrderBy(r => r.Name));

And its coming up with:

+ Error {System.Windows.Ria.Data.EntityOperationException: Object reference not set to an instance of an object.

at System.Windows.Ria.Data.HttpDomainClient.GetRequestResult(HttpDomainClientAsyncResult httpAsyncResult)

at System.Windows.Ria.Data.HttpDomainClient.EndQueryCore(IAsyncResult asyncResult)

at System.Windows.Ria.Data.DomainClient.EndQuery(IAsyncResult asyncResult)

at System.Windows.Ria.Data.DomainContext.CompleteLoad(IAsyncResult asyncResult)} System.Exception {System.Windows.Ria.Data.EntityOperationException}

Any ideas?

re: Entity Framework Include with Func

DonSleza4e — Wed, 17 Jun 2009 12:27:23 GMT

Thanks, thats I looking for!

Amazing!

re: Entity Framework Include with Func

Matthieu MEZIL — Wed, 17 Jun 2009 11:57:07 GMT

You can do :

context.Products.Include(p => p.Category).Include(p => p.OrderDetails);

If you want more level, you should look at it.

re: Entity Framework Include with Func

DonSleza4e — Wed, 17 Jun 2009 11:17:47 GMT

What about including several tables?

for example, load shops and categories with products

What about DataLoadOptions for Entity Framework ObjectContext?

VS2010学习 — Mon, 15 Jun 2009 17:28:08 GMT

What about DataLoadOptions for Entity Framework ObjectContext? I think the proper way to start this post

re: Entity Framework Include with Func

Matthieu MEZIL — Fri, 14 Nov 2008 20:51:48 GMT

Hi Alessandro,

In VB, you must change it like this:

Module ObjectQueryExtension
    <Extension()> _
    Function Include(Of T)(ByVal mainQuery As ObjectQuery(Of T), ByVal subSelector As Expression (Of Func (Of T, Object)))
        Return mainQuery.Include(CType(CType(CType(subSelector.Body, UnaryExpression).Operand, MemberExpression).Member, PropertyInfo).Name)
    End Function
End Module

re: Entity Framework Include with Func

Alessandro Del Sole [VB MVP] — Fri, 14 Nov 2008 08:46:36 GMT

Hi, I'm trying to convert the extension method above into VB. But I get an exception. Here's my VB translation:

<Extension()> Module Module1

<Extension()> Function Include(Of T)(ByVal mainQuery As ObjectQuery(Of T), ByVal subSelector As Expressions.BLOCKED EXPRESSION

End Function

End Module

The exception I get is that an UnaryExpression cannot be converted into MemberExpression. Any suggestions?

Thank you!

re: Entity Framework Include with Func

Matthieu MEZIL — Fri, 24 Oct 2008 12:29:18 GMT

@eXcess : I also think so but I did no test. I just want to remind you that it's a POC.

Martin should try it in a production application this week. I am very interested to know if it is usable in a real world application.

re: Entity Framework Include with Func

eXcess — Fri, 24 Oct 2008 12:18:04 GMT

It does use Reflection though, but that won't cause a performance drop I suppose?

re: Entity Framework Include with Func

Matthieu MEZIL — Thu, 09 Oct 2008 07:04:03 GMT

My Include method is an extension method (keyword this before the first parameter).

Moreover, when you do: c => c.Products (which is a lambda expression), you have an Expression<Func<Category, object> and so I can treat it.

re: Entity Framework Include with Func

Jared Wein — Tue, 07 Oct 2008 19:39:32 GMT

Hi Matthieu,

Can you explain how this static class and it's static method are interpreted in to the framework to allow this behavior?

I don't see any use of the partial or override keyword here.

re: Entity Framework Include with Func

Matthieu MEZIL — Mon, 11 Aug 2008 19:06:23 GMT

Like this msmvps.com/.../entity-framework-include-with-func-next.aspx

re: Entity Framework Include with Func

Robert — Mon, 11 Aug 2008 19:01:53 GMT

How would you do a nested includes, something like getting the manufacturer from a product.

Where I would just write .Include("Products").Include("Products.Manufacturer");

context.Categories.Include(c => c.Products).Include(c.Products.Any(p => p.Manufacturer);

How would you do that?

Entity Framework Include with Func

Jiří {x2} Činčura — Tue, 29 Jul 2008 12:15:21 GMT

Really good extension method. msmvps.com/.../entityframework-include-with-func.asp

Entity Framework Include with Func

Jiří {x2} Činčura — Tue, 29 Jul 2008 12:14:55 GMT

msmvps.com/.../entityframework-include-with-func.aspx

re: Entity Framework Include with Func

Matthieu MEZIL — Thu, 17 Jul 2008 12:02:00 GMT

First, Include is an extension method.

So you need to add the using of the ObjectQueryExtension in your file which will use the Include method.

Moreover, Include is not an extension method for entity class but for ObjectQuery<T>.

re: Entity Framework Include with Func

Nilotpal — Thu, 17 Jul 2008 11:53:24 GMT

I can't see the include() method in my entity class... Why I wonder... my email is nilotpal.das@microsoft.com would you be able to help...?

re: Entity Framework Include with Func

Matthieu MEZIL — Tue, 10 Jun 2008 19:34:21 GMT

Daniel Simmons propose what is probably the best way for you:

Patient AttachContacts(Patient patient, IEnumerable<PatientContact> contacts)
{
    patient.PATIENTCONTACTS.Attach(contacts);
    return patient;
}
 
var q = from patient in datacontext.PATIENTS
        select new { Patient = patient, PatientActiveContacts = patient.PATIENTCONTACTS.Where(c => c.ISACTIVE == "T") };
var fullQuery = from anonType in q.AsEnumerable()
                select AttachContacts(anonType.Patient, anonType.PatientActiveContacts);

re: Entity Framework Include with Func

Matthieu MEZIL — Tue, 10 Jun 2008 13:28:10 GMT

Else, of course, you can create a type with Patient and PatientActiveContacts properties and use the first query without anonymous type.