Usage of repository between EF model and code consumer

Posted by jim on Programmers See other posts from Programmers or by jim
Published on 2012-03-31T16:06:00Z Indexed on 2012/03/31 17:42 UTC
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I have binary data in my database that I'll have to convert to bitmap at some point. I was thinking whether or not it's appropriate to use a repository and do it there. My consumer, which is a presentation layer, will use this repository. For example:

// This is a class I created for modeling the item as is.
public class RealItem
{
    public string Name { get; set; }
    public Bitmap Image { get; set; }
}

public abstract class BaseRepository
{
    //using Unity (http://unity.codeplex.com) to inject the dependancy of entity context.
    [Dependency]
    public Context { get; set; }
}

public calss ItemRepository : BaseRepository
{
    public List<Items> Select()
    {
        IEnumerable<Items> items = from item in Context.Items select item;
        List<RealItem> lst = new List<RealItem>();
        foreach(itm in items)
        {
            MemoryStream stream = new MemoryStream(itm.Image);
            Bitmap image = (Bitmap)Image.FromStream(stream);
            RealItem ritem = new RealItem{ Name=item.Name, Image=image };
            lst.Add(ritem);
        }

        return lst;
    }
}

Is this a correct way to use the repository pattern? I'm learning this pattern and I've seen a lot of examples online that are using a repository but when I looked at their source code... for example:

public IQueryable<object> Select
{
    return from q in base.Context select q;
}

as you can see no behavior is added to the system by their approach, so I was confused that maybe repository is something else and I got it all wrong. At the end there should be extra benifits of using them right?

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