c# 4.0 - Workarounds for using custom methods/extension methods in LINQ to Entities

Question

I have defined a GenericRepository class which does the db interaction.

 protected GenericRepository rep = new GenericRepository();

And in my BLL classes, I can query the db like:

public List<Album> GetVisibleAlbums(int accessLevel)
{
    return rep.Find<Album>(a => a.AccessLevel.BinaryAnd(accessLevel)).ToList();  
}  

BinaryAnd is an extension method which checks two int values bit by bit. e.g. AccessLevel=5 => AccessLevel.BinaryAnd(5) and AccessLevel.binaryAnd(1) both return true.

However I cannot use this extension method in my LINQ queries. I get a runtime error as follows:
LINQ to Entities does not recognize the method 'Boolean BinaryAnd(System.Object, System.Object)' method, and this method cannot be translated into a store expression.

Also tried changing it to a custom method but no luck. What are the workarounds?

Should I get all the albums and then iterate them through a foreach loop and pick those which match the AccessLevels?

Answer 1

I realize this already has an accepted answer, I just thought I'd post this in case someone wanted to try writing a LINQ expression interceptor.

So... here is what I did to make translatable custom extension methods: Code Sample

I don't believe this to be a finished solution, but it should hopefully provide a good starting point for anyone brave enough to see it through to completion.