Question

Why is it not possible to do this:

public static void Init<TEntity>(params TEntity[] repositories) where TEntity : Entity
{
    foreach (TEntity item in repositories)
    {
       Repository<item> rep = new Repository<item>();
    }
}

The above code won’t compile: Cannot resolve symbol item

Yet this works:

public static void Init<TEntity>(TEntity entity) where TEntity : Entity
{
    Repository<TEntity> rep = new Repository<TEntity>();
}

EDIT

I’m editing the OP to give a bigger picture of the problem. We are experiencing some issues with the entity framework Db Context being spawned by multiple repositories. Currently we access the repositories like:

Repository<Product> rep = new Repository<Product>()
Repository<Account> rep = new Repository<Account>()

Since there’s a relationship between product and account EF will complain about objects being attached to a different context. So we are trying to resolve this issue by consolidating repository access into a Unit of Work pattern:

Here’s an example of what I’m trying to achieve:

public class UnitOfWork
{
    protected List<Entity> Repositories = new List<Entity>();
    private readonly DbContext _context;
    protected UnitOfWork()
    {
       _context = new SqlDbContext();
    }

    public static UnitOfWork Init<TEntity>(params TEntity[] repositories) where TEntity : Entity
    {
            UnitOfWork uow = new UnitOfWork();
        foreach (TEntity item in repositories)
        {
            Repository<item> rep = new Repository<item>();
            uow.Repositories.Add(rep);
        }
            return uow;
    }

    public IRepository<T> GetRepository<T>() where T : Entity
    {
        return Repositories.OfType<T>().Single();
    }   
}

So we can access our repositories like:

GetRepository<Product>().GetById(1);
GetRepository<Account>().GetById(123434);

Answer 1

item is an instance of a type, but you need a type parameter to create an instance of your generic Repository<T> class.