UnitOfWorkScope in WCF service

Hi,

I am using Lightspeed 4 Pro for quite a while. Recently I've had to create a WCF service using Lightspeed but I am having trouble with it. First, the usual PerRequestUnitOfWorkScope gives null object exception when referencing Current property. It is logical because WCF service doesn't hold HttpContext in it, so that's probably why the PerRequestUnitOfWorkScope doesn't work. My WCF service is implemented as a clear separation from Silverlight client using DTO objects.

Now, what kind of scope class should I use instead?

I've tried to create my own implementation of UnitOfWorkScopeBase, but unfortunately OperationContext.Current (which seems like a logical place to hold references to unit of work) is not always available in WCF services.

Any help is appreciated.

public class Global : System.Web.HttpApplication
{
    private static LightSpeedContext<PosjedovniListoviModelUnitOfWork> context = new LightSpeedContext<PosjedovniListoviModelUnitOfWork>("Izmjera");

    public static LightSpeedContext<PosjedovniListoviModelUnitOfWork> PosjedovniListoviModelContext
    {
        get { return Global.context; }
    }
    ...
    protected void Application_EndRequest(object sender, EventArgs e)
    {
        SimpleUnitOfWorkScope<PosjedovniListoviModelUnitOfWork> scope = new SimpleUnitOfWorkScope<PosjedovniListoviModelUnitOfWork>(context);

        if (scope.HasCurrent)
            scope.Current.Dispose();
    }
}

That's the way I instantiate context. It's done in HttpApplication. Last thing I've tried is using SimpleUnitOfWorkScope. Scope is created in service instance below.

    public class PosjedovniListoviServis : IPosjedovniListoviServis
    {
    #region Fields (1)

    private PosjedovniListoviKontroler _kontroler;
    private PosjedovniListoviLightspeedDao _dao;
    private SimpleUnitOfWorkScope<PosjedovniListoviModelUnitOfWork> _scopeHolder = new SimpleUnitOfWorkScope<PosjedovniListoviModelUnitOfWork>(Global.PosjedovniListoviModelContext);

    #endregion Fields

    #region Constructors (1)

    public PosjedovniListoviServis()
    {
        //_dao = new PosjedovniListoviLightspeedDao(Global.PosjedovniListoviModelContext);
        _dao = new PosjedovniListoviLightspeedDao(_scopeHolder.Current);
        _kontroler = new PosjedovniListoviKontroler(_dao);
    }

    #endregion Constructors

The problem with this solution is that doesn't exactly dispose unit of work and Oracle (underlying DB) connections multiply by each WCF request. If I put PerRequestUnitOfWorkScope in place of SimpleUnitOfWorkScope I get null reference exception when trying to use _scopeHolder.Current.

Ok, I've found the solution and I'll post it here for others.

PerRequestUnitOfWorkScope can work in WCF service. You need to do the following.

1. Turn on compatibility asp.net compatibility mode in web.config:

2. Mark the wcf service class with following attribute:

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]

After that, PerRequestUnitOfWorkScope is working correctly and you can use the usual strategy as dealing with ASP.Net WebForms application (User Guide).

Regards,

Milivoj