Access binary data of an SPFile through an SPMetal generated entity

Question

I've used SPMetal to generate my DataContext and classes for my custom Content Types. Some of these Content Types derive from Document content type.

I need to run a Linq query against a Document Library and access the binary data for each of the files returned. The documents are returned nicely as the expected Entity types.

My problem is that I can't really figure out how to do the equivalent of SPFile.OpenBinaryStream() when all I have is a reference to my entity, without having to fetch the SPFile from the containing SPList by the document's ID first.

Any suggestions?

Thanks

Answer 1

I am thinking of giving ICustomMapping a go to create a ListItem property on my Entities of type SPListItem and use MapFrom() set it to be the item which it represents. I am just worried about object lifetime/disposal issues, i.e. I'm not sure if the ancestor path of the Item's SPList (SPWeb>SPSite) is still open after the Entity's properties have been populated.

Answer 2

There's the SPMetal Extender on CodePlex which might help, but I think you're gonna have to extend the entity further by adding a property to it which returns a Stream, and is effectively a proxy call to the object model.

Of course, as soon as you need to run SPMetal again, you'll loose the custom property.

Then again, you might be able to create an extension method in your own class which will add an OpenBinaryStream proxy call through the entity class... (thinking about it, this is probably the best solution).

Answer 3

1. Get your Web var web = SPContext.Current.Web
2. Create your file location var location = Path.Combine(entity.Path, entity.Name)
3. call SPFile file = _web.GetFile(_location)

Easier if you write it as a static extension method for the SPFile class.