Using a DomainService with CRUD statements (Silverlight)

In my DomainService which is accessing a ADO.NET (.edmx) file I have the following function which returns ALL columns

Public Function GetOpenPOs() As IQueryable(Of PartNumberHistory)
        Return Me.ObjectContext.PartNumberHistories.Where(Function(e) e.OpenClosed = "OPEN PO" And e.NumOfQty = 1 And e.LineItem = 1).OrderBy(Function(e) e.PO)
    End Function

This works great and when I edit the grid and click "Submit Changes" button - everything is saved - works like a charm

Problem is I *want* to only return (and be able to edit) a few of the columns....

I try this function

Public Function GetOpenPOs() As IQueryable(Of PartNumberHistory)
        Return Me.ObjectContext.PartNumberHistories.Where(Function(e) e.OpenClosed = "OPEN PO" And e.NumOfQty = 1 And e.LineItem = 1).OrderBy(Function(e) e.PO).Select(Function(e) e.PO)
    End Function

But get the error:
Error      1      'System.Linq.IQueryable(Of String)' cannot be converted to 'System.Linq.IQueryable(Of BusinessApplication9.PartNumberHistory)' because 'String' is not derived from 'BusinessApplication9.PartNumberHistory', as required for the 'Out' generic parameter 'T' in 'Interface IQueryable(Of Out T)'.

How can I make this work?  The client seeing all of the columns is just overkill

Thanks!
ProdigyOne2kAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

tovvenkiCommented:
Hi,
See if this helps you
http://forums.silverlight.net/forums/p/171512/387088.aspx

Thanks and regards,
Venki
0
vbighamCommented:
The select statement on the end is changing your return type.  Try removing that, and you should get a list of the entities back.

like this:

Return Me.ObjectContext.PartNumberHistories.Where(Function(e) e.OpenClosed = "OPEN PO" And e.NumOfQty = 1 And e.LineItem = 1).OrderBy(Function(e) e.PO)
0
vbighamCommented:
I would just not show any columns that don't apply, but I don't think that these domain services will allow you to return an IQueryable(Of String).  

If I remember right it tells you that is not a valid entity type.  You could try changing  IQueryable(Of PartNumberHistory) to IQueryable(Of String) to see what I mean.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft Development

From novice to tech pro — start learning today.