Entity Reference Not Loading Implicitly?

Question

I'm using .NET 3.5 and I'm having trouble loading the Entity References automatically. Ideally, and it seems to work sometimes, I would like something like

Dim relocations = ctx.EmployeeRelocations.Where(Function(o) o.Employee.EmployeeNumber = employeeNumber).ToList()
If Not relocations.Where(Function(o) o.ValidTerritory.Territory = territory).Any() Then

where ValidTerritory is a reference type in relocations. But instead, when I try that, I get Object Not set to an instance... for o.ValidTerritory. So, I can do this and everything works fine:

If Not relocations.Where(Function(o)
                             o.ValidTerritoryReference.Load()
                             Return o.ValidTerritory.Territory = territory
                         End Function).Any() Then

In theory, it makes sense what's happening, but I don't understand why I need the explicit Load and why this behavior seems to come and go (that is, it sometimes loads the references fine with no explicit load).

MarcinJuraszek · Accepted Answer · 2012-04-12 20:08:09Z

1

Try using Include to get that data:

relocations.Include("ValidTerritory").Where(Function(o) o.ValidTerritory.Territory = territory).Any()

answered Apr 12, 2012 at 20:08

MarcinJuraszek

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4 Comments

mafafu Over a year ago

I got 'Include' is not a member of 'System.Collections.Generic.List(Of ...EmployeeRelocation)' where relocations is defined Dim relocations = ctx.EmployeeRelocations.Where(Function(o) o.Employee.EmployeeNumber = employeeNumber).ToList() Also note that digging into the Employee reference here works just fine...

MarcinJuraszek Over a year ago

.Include has to be made directly on context.Table element, so in your example it would be ctx.EmployeeRelocations.Include("ValidTerritory").

mafafu Over a year ago

That got rid of the error, but caused further issues with my queries. It also made the statement more complex than it seems it should have to be since that type of referencing is working in other places. I don't think I can mark this as accepted because the underlying issue is still there, but +1 for the help.

mafafu Over a year ago

I just went back and revisited this when I got some time and also found this question which basically said the same thing and that this was essentially by design. I learned a good bit about EF that I didn't know when I started the project this was a part of. And you were spot on with your answer; I'm not sure why I had trouble with it the first time through.

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