Using lambda expressions in a query

Question

I am running this query on a Windows Azure Web Role, and need to get a related entity set, but my lambda expression doesn't seem to be working.

 var query = from p in applicationsContext.Programs.Expand(p => p.Campus)
                    where p.ProgramId == Int32.Parse(programsList.SelectedValue)
                    select p;

I am using System.Linq andSystem.Data.Entities already, but the lambda expression (p => p.Campus) causes the error:

Cannot convert lambda expression to type string because it is not a delegate type

Any idea as to why this wouldn't work?

EDIT: Intellisence also doesn't seem to recognize the 'p' in the lambda expression, that might be part of the problem.

Expand expects a sting, not a delegate. Maybe just "Campus" would work? — jessehouwing
– jessehouwing, Commented Dec 14, 2013 at 19:04

jessehouwing · Accepted Answer · 2013-12-14 14:38:17Z

2

I think Expand must get string parameter (link). Then you can't use delegate instead string.

edited Dec 14, 2013 at 14:38

jessehouwing

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answered Dec 14, 2013 at 14:24

Boris Parfenenkov

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3 Comments

BobHy Over a year ago

Agree, that's the reason.

Centimane Over a year ago

So what would be the fix? What sort of link would I be putting in?

Boris Parfenenkov Over a year ago

If Campus is int, you don't need Expand this property. If Campus is related entity, then use Expand("Campus")

BobHy · Accepted Answer · 2013-12-14 14:06:59Z

0

I'll hazard a guess: is p.Campus something other than string type?

answered Dec 14, 2013 at 14:06

BobHy

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1 Comment

Centimane Over a year ago

p.Campus is an int, but judging from the example I'm working off of that shouldn't effect it

Igorek · Accepted Answer · 2013-12-16 15:11:27Z

0

Not sure what data source you're going against, but do not re-use the same 'p' for the inner Expand statement:

 var query = from p in applicationsContext.Programs.Expand(t => t.Campus)
                    where p.ProgramId == Int32.Parse(programsList.SelectedValue)
                    select p;

answered Dec 16, 2013 at 15:11

Igorek

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