Build error

wilkov · November 5th, 2010, 11:10 AM

Hello,

Im getting this annoying build error on chapter 3 and cant seem to resolve it.
It happens when building the silverlight project rather than the web project and results in me not being able to access the WebContext class.

The actual error is 'Sequence contains more than one element'
My setup is as follows
Visual Studio 2010 Pro
Silverlight 4 tools for VS2010
Silverlight 4 SDK
RIA services toolkit v4.0.50506.0
RIA Services v1.0 v4.0.50506.0

The detailed error is as follows (in MSBuild log)

C:\Program Files (x86)\MSBuild\Microsoft\Silverlight\v4.0\Microsoft .Ria.Client.targets(303,5): error : Sequence contains more than one element
Generating proxy classes for the DomainService 'DartsStats.Web.Services.AuthenticationService'.
Generating WebContext class.
The client proxy task generated or is reusing existing copies of these files:
RIA client proxy class generation finished in 0.425 seconds.
Done executing task "CreateRiaClientFilesTask" -- FAILED.
Done building target "CreateRiaClientFiles" in project "DartsStats.csproj" -- FAILED.

Ive started from scratch twice but to no avail
NB when i initially start the project and select 'enable RIA services' I CAN access the WebContext class its only after this error that I cant.

Any help much appreciated
Scott Williamosn

Gabor66 · November 7th, 2010, 03:23 AM

Does the WebContext object is in App.xaml file as ApplicationLifetimeObject?

Code:

    <Application.ApplicationLifetimeObjects>
         <app:WebContext>
            <app:WebContext.Authentication>
                <services:FormsAuthentication />
            </app:WebContext.Authentication>
        </app:WebContext>
    </Application.ApplicationLifetimeObjects>

wilkov · November 8th, 2010, 10:46 AM

Hi Gabor,
Thanks for the reply. Ive got that in app.xaml but <app:WebContext> is not recognised (through intellisense).
Ive double checked correct namespaces. Its strange as before this build error no problems with WebContext

wilkov · November 8th, 2010, 12:44 PM

Right Ive just rebuilt my PC and have a nice new clean build of all Visual Studio 2010 Pro, Silverlight 4 etc etc

When using the downloaded code from Wrox I can get a clean build but as soon as I add a Domain Service I get the error message 'Sequence can only contain one element' and the WebContext doesnt resolve.

The error is occuring in the microsoft.ria.client.targets dll in C:/MSBuild folder

TBH I cant get through this problem as its definetly not related to my setup and am going to have to give up on the book or perhaps try the entity framework

Id be interested to hear if anyone else is getting this problem with RIA Services

Gabor66 · November 9th, 2010, 03:15 AM

Did You install the RIA Services toolkit? The Microsoft moved the Linq2Sql to there. The standard RIA services doesn't install the Linq2Sql Domain Context, as described in this thread:

LINQ to SQL Context not visible to Domain Service Class (P 114)

wilkov · November 9th, 2010, 05:43 AM

Yes I have the latest RIA Toolkit but still getting the problems. Im giving up on LinqToSql and going to try the EF.

The author has picked the wrong technology there but cant really blame him as MS has only recently decided to phase out LinqToSQL. A pain if following the book closely though

Gabor66 · November 18th, 2010, 03:26 AM

The author claimed in april, that LINQ2SQL is lighter, simpler and quicker than EF, and if You don't want to port the dataaccess to a database other than MS SQL server, this is a reasonable choice.

From that time nothig changed, the EF v.4. is the same as was in that time. (The new version is in CTP only).

Because in my application LINQ2SQL works perfectly, in your application the problem caused not by LINQ2SQL per se; maybe some settings are missed.

Switching to EF (wich isn't as easy as seemed) may not remedies Your problem.

Please let me know if found any solution

Gabor