Question

I am trying to build the internet-shop using MVC3. I am using EF and I have one interface to work with my entity context:

public interface IBaseRepository<T> where T : class, IBase, new()
{
    IQueryable<T> Get();
}

and one abstract class to work with this interface:

 public abstract class BaseRepository<T> : 
       IBaseRepository<T> where T : class, IBase, new()
{
    protected abstract ObjectSet<T> EntitySet { get; }

    public virtual IQueryable<T> Get()
    {
        return from obj in EntitySet select obj;
    }
}

So I can use this solution to work with different tables in my database(SQL). I can’t post images yet. So I will try to describe my database:

[Product] – [CategoryProduct(ProductID,CategoryID)] – [Category(ShortName)]

1. Table Product
2. Table Category with field ShortName
3. Table CategoryProduct with fields ProductID,CategoryID to make many-to-many link.

(We are getting closer to the problem….)

I have a method, which take “ShortName” from Table “Category”(“repository” is the dbcontext only for one table – “Category”) And I need to return IEnumerable<> of Products in my view:

public ActionResult GetProductInCategory(string shortName)
{
       IEnumerable<Product> = repository.Get()......
        return View();
}

So here is the problem: I need to make a query to take product from these 3 tables using lambda, but i can’t understand, how to do this.

I can’t use linq, because I have direct access only to one table in the whole database.

Sorry for bad eplanation, if you have any questions about architecture to get the whole view, I will try to answer you.

Answer 1

I’m assuming/guessing from your use of the EntitySet you’re using EntityFramework and you have this structure in you Entity Classes

Category
+ShortName
+EntityCollection<CategoryProduct> CategoryProduct

CategoryProduct
+Product

So you could do this in your linq query:

BaseRepository<Category> repository = //get your CATEGORY repository
IEnumerable<Product> = repository.Get().Where(c=> c.ShortName == shortName)
                                       .SelectMany(cp => cp.CategoryProduct)
                                       .Select(p => p.Product).ToList();