DevForce Community Forum : EntityServerException with children reference http://www.ideablade.com/forum/ This is an XML content feed of; DevForce Community Forum : DevForce 2009 : EntityServerException with children reference Sat, 11 Apr 2026 23:38:48 -700 Thu, 01 May 2008 18:51:09 -700 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 9.69 360 www.ideablade.com/forum/RSS_post_feed.asp?TID=794 DevForce Community Forum http://www.ideablade.com/forum/forum_images/IdeaBlade_logo_tm.png http://www.ideablade.com/forum/ EntityServerException with children reference : Well ... we do keep pushing the... http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2924#2924 Author: kimj
Subject: 794
Posted: 01-May-2008 at 6:51pm

Well ... we do keep pushing the date for Beta2 off, don't we? Smile 
 
Right now, we're looking at mid-May (yes, 2-3 weeks from now).
]]> Thu, 01 May 2008 18:51:09 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2924#2924 EntityServerException with children reference : Awesome. Thanks, Kim. When... http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2923#2923 Author: philpastor
Subject: 794
Posted: 01-May-2008 at 5:42pm

 
Awesome. Thanks, Kim. When are those bits going to be released? :)


Edited by philpastor - 01-May-2008 at 5:44pm]]> Thu, 01 May 2008 17:42:56 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2923#2923 EntityServerException with children reference : Oh, you're not doing anything... http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2921#2921 Author: kimj
Subject: 794
Posted: 01-May-2008 at 2:26pm

Oh, you're not doing anything wrong, it looks like we do have a bug.
 
What's happening is that when the first query executed for a given type (like Customer) is one which forces immediate execution, i.e., a query using First, Max, Count, etc., then we're not correctly doing some initialization required to handle related entities.  When we attempt to retrieve the related entities and none are returned we get the unhandled sequence exception you see.  You've found a unique case, since if you'd first queried for a Customer using deferred execution the error wouldn't have occurred; also if you'd done a First() query on a customer having orders the problem wouldn't have surfaced.
 
The good news - due to some refactoring we've already done in query processing -  is that this problem has already been fixed in our latest bits. 
 
For your purposes right now, I guess the workaround could be to try to avoid using "immediate execution" type of queries.  In this case, a ToList() followed by a First(), like this:
 
    aManager.Customers.Where(c => c.CustomerID == "PARIS").ToList().First();
 
would avoid the problem.
 
Thanks for bringing this to our attention.
]]> Thu, 01 May 2008 14:26:35 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2921#2921 EntityServerException with children reference : Kim, Thank you for the response. This... http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2919#2919 Author: philpastor
Subject: 794
Posted: 01-May-2008 at 11:15am

Kim,
 
Thank you for the response.
 
This may be my lack of understanding of LINQ, but using the tutorial and the Northwind database I executed the following commands:
 
aManager = new DomainModel.Manager();
DomainModel.Customer aCustomer = aManager.Customers.Where(c => c.CustomerID == "PARIS").First();
System.Diagnostics.Debug.WriteLine(string.Format("Customer Id: {0} - Number of Orders: {1}", aCustomer.CustomerID, aCustomer.Orders.Count));

This results in the exception. In this example the customer "PARIS" has no orders. Does the First() method sever the ability to lazy load? 

If I change it to the following, then it works just fine:
aManager = new DomainModel.Manager();
var query = aManager.Customers.Where(c => c.City.Length == 5);
foreach (DomainModel.Customer aCustomer in query)
{
Console.WriteLine(string.Format("Customer Id: {0} - Number of Orders: {1}",aCustomer.CustomerID, aCustomer.Orders.Count));
}

]]> Thu, 01 May 2008 11:15:19 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2919#2919 EntityServerException with children reference : How are you accessing the child... http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2917#2917 Author: kimj
Subject: 794
Posted: 01-May-2008 at 8:27am

How are you accessing the child collection?  Something simple like:

   var list = Company.Employees;
 
or more complex:
 
   var list = Company.Employees.Skip(2).Take(2);
 
 
These should actually work, but we need a little more information to help uncover the problem.   Are you able to recreate the problem using any of the tutorials?
]]> Thu, 01 May 2008 08:27:25 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2917#2917 EntityServerException with children reference : I am receiving an "EntityServerException:... http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2911#2911 Author: philpastor
Subject: 794
Posted: 30-Apr-2008 at 10:15am

 
I am receiving an "EntityServerException: Sequence contains no elements" when I try to navigate to an association property that does not have any children.
 
I have a Company object that contains a collection of Employees. I expected that if there were no employees I would receive an empty List<Employee> collection. But instead I received the exception. What is the correct way to determine whether or not this collection is empty?
 
Just as a note, if I create an employee in the database, then the Employee is returned in the association (so the model is wired up correctly).
 
Phil
 
]]> Wed, 30 Apr 2008 10:15:35 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=794&PID=2911#2911