I have an entity called Person who has a collection o开发者_StackOverflow社区f addresses.
I created:
public partial class Person
{
public int AddressCount{get{return Addresses.Count;}}
}
This returns the error:
The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.
I am returning a collection of people, how can I do this without doing this:
public int AddressCount
{
get
{
using (var c = new Entities())
{
return c.People.Where(s => s.PersonId == PersonId).Single().Addresses.Count;
}
}
}
I've found that this works to eager-load a "count" property without loading all the entities in the collection:
using (var context = new Entities())
{
var people = (from p in c.People
select new
{
Person = p,
AddressCount = p.Addresses.Count
}).ToList();
foreach (var item in people)
{
item.Person.AddressCount = item.AddressCount;
}
}
The drawback, of course, is that AddressCount needs to be settable. I guess you could give it an internal setter if your context is in the same assembly as the entity class.
You may not need the Include("Addresses")
on there - that's worth testing. Edit removed it since it's not necssary (and may in fact make the query do more work than it has to).
精彩评论