I am using ViewModels that use IRepository<TEntity>. I had methods on the IRepository that would return EntitySet<TEntity>. The problem with them, was that I was not able to create EntitySets for a unit test...
I solved that problem by just having the repository process the results and return back a List or ObservableCollection. I was only using EntitySets because of a control I was using, so I just ripped apart their source code and replaced the underlying EntitySet collection with an ObservableCollection. Up until that point I had everything working well and decoupled. The entire ViewModel just had ObservableCollections and IRepository<TEntity> and was completely unit testable. View -> ViewModel -> IRepository -> Ria DataContext The next problem came when I tried to apply paging on top of this. I created a new PagingCollection<TEntity> to hold this. It implements the IPagableCollectionView interface, which all paging grids use (builtin silverlight, Telerik, etc.). The grid would make the calls to the interface that it was paging, and the PagingCollection<TEntity> would automatically pass on the correct parameters to the repository. The problem I had then was how can you apply arbitrary filtering to your grid through a repository. You can filter a grid by any column and you need those to go through. Creating 50 methods/parameters on a repository isn't feasible. So I tried to get my grid/PagingCollection to work on the IQueryable. *The problem being you can not assign an IQueryable object to the datacontext* You can create your own IQueryable with Enumerable.Empty<TEntity>.AsQueryable(). Usually you could just union that with a query you already have going. If you could do that, you could pass your IQueryable down to the datacontext and everything would be fine. However you can only GET the IQueryable from a datacontext, you can not SET it. And they have not exposed the .Union() method on the datacontext query. If they did expose either a union or a way to set the IQueryable, then it would be possible to have a completely decoupled viewmodel that allowed you to do arbitrary paging & filtering :-( -David Burela On 3 September 2010 16:18, Steven Nagy <steven.n...@readify.net> wrote: > Hi David, > > > > We are using RIA and a standard ViewModel takes an IRepository<T> where T : > Entity. > > When I want to track lists of items I use ObservableCollection<T> as well > and add it to the EntitySet if I want it commited to the database. > > Under the hood, an IRepository<Product> and IRepository<Category> will use > the same domain context however we are in the process of adjusting this to > use the same domain context only per ViewModel (ie unit of work) and this is > managed by the IOC container. > > > > However I never really need to create NEW entity sets and was unsure how to > answer your question. Usually with .Include(“Products”) you would get all > the products with a category, or at least an empty entity set if there are > none, and you can still add to that existing entity set on the Category > entity. > > > > *Steven Nagy > *Readify | Senior Consultant > > M: +61 404 044 513 | E: steven.n...@readify.net | B: azure.snagy.name > > > > *From:* ozsilverlight-boun...@ozsilverlight.com [mailto: > ozsilverlight-boun...@ozsilverlight.com] *On Behalf Of *David Burela > *Sent:* Thursday, 2 September 2010 4:45 PM > *To:* ozSilverlight > *Subject:* Re: Decoupling from RIA services > > > > Answer: Just hack it out and use an ObservableCollection instead. > > > > On 2 September 2010 14:10, David Burela <david.bur...@gmail.com> wrote: > > I am working on a new Silverlight application. > > It is a standard MVVM application using RIA services to retrieve the data. > > > > I am trying to not have the domain service in my ViewModel, and I have > managed to get 99% of the domain context out. > > The only thing that I am just left with, is a EntitySet<> as the base of > one of my collections, which I'm not too worried about. But for testing, > etc. I need to be able to new up one of these. > > > > When i go > > var entityset = new EnitySet<Products>(); > > It does create a new EntitySet. However, it doesn't initialise it's > internal list. So when I try to add items to it in my tests the whole thing > throws null reference exceptions. Does anyone have a way of creating > EntitySets client side so I can have everything decoupled from my domain > context? > > > > -David Burela > > > > _______________________________________________ > ozsilverlight mailing list > ozsilverlight@ozsilverlight.com > http://prdlxvm0001.codify.net/mailman/listinfo/ozsilverlight > >
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