LINQ To SQL

re: LINQ To SQL

collection_knowledge — Wed, 20 May 2009 03:27:17 GMT

Hi Jesse,

I have a problem in my code, I'm a newbie in silverlight. My problem is in joing two tables and select only the specific columns.

Here is my code:

Public Function GetParentAndChildList() As Object Implements IChannelService.GetParentAndChildList

Dim db As ChannelDataContext = New ChannelDataContext

Dim channelMatch = From channelRow In db.channels _

Join parentChild In db.ChannelParentChildListings _

On channelRow.channel_id Equals parentChild.parent_id _

Where channelRow.parent_id.Equals(0) _

Order By channelRow.title Ascending _

Select channelRow.channel_id, channelRow.title, parentChild.child, parentChild.child_id

Return channelMatch <-------- Error throw Unable to cast object of type

'System.Data.Linq.DataQuery`1[VB$AnonymousType_1`4[System.Int32,System.String,System.String,System.Nullable`1[System.Int32]]]' to type 'System.Collections.Generic.List`1[Media.channel]'.

End Function

Hope you could help me. Thanks

re: LINQ To SQL

wisecarver — Fri, 28 Mar 2008 01:05:59 GMT

You surprised me bro...

Didn't list the current best book on LINQ.

www.amazon.com/.../1933988169

re: LINQ To SQL

Rubicon — Wed, 26 Mar 2008 19:10:34 GMT

Hi Jesse, great work your doing on SL2

In the upcoming tutorial would you be able to demonstrate how to format eg. a Date in the code-behind file. What I mean is, if the data in the database is not in a proper format how do you convert it when retrieved using LINQ, are you able to do it both in the code-behind file as well as in the XAML-code?

Thanks

Arne

re: LINQ To SQL

BenHayat — Wed, 26 Mar 2008 18:55:09 GMT

>>Ben, I didn't but after you read the tutorial if you still want that let me know and I'll do a blog entry on it. However, it really isn't silverlight, it's just LINQ<<

I'm pretty comfortable with LINQ2SQL, what want to find out is the communication and data transfer between client and middle tier when creating/updating records.

I think until MS come out with a std approach for data handling out-of-the-box, we need to have some sort of guidelines how it should be done to maintain proper tracking and concurrency between client <-> data service <-> Database Server.

re: LINQ To SQL

jesseliberty — Wed, 26 Mar 2008 18:31:20 GMT

Ben, I didn't but after you read the tutorial if you still want that let me know and I'll do a blog entry on it. However, it really isn't silverlight, it's just LINQ

re: LINQ To SQL

BenHayat — Wed, 26 Mar 2008 18:24:24 GMT

Jesse, when you create this tutorial for SL, could you please show the four operations (Create, Retrieve, Update and Delete)?

Thanks!

..Ben