Multiple includes using Entity Framework and Repository Pattern

Question

I am using Entity Framework and a Repository Pattern for all my data access, when using table navigation I have noticed that 2 queries are being run when I got the first object and reference a field in a navigation object. As I have lots of relationships in the database using this technique for my navigation properties may cause performance overheads.

I have looked into the Include(string tableName) method and this will work really well (if I was not using a generic RP) but this only takes one table name. I have managed to replicate this in my repository pattern for one include by changing my where from classs to EntityObject but how can I have multiple includes in one query using a repository pattern??

here is my code:

public class GenericRepository<T> : IRepository<T> where T : EntityObject, new()
{
    private Entities _Context;
    private ObjectSet<T> _ObjectSet;

    public IQueryable<T> FindBy(System.Linq.Expressions.Expression<Func<T, bool>> predicate, string include)
    {
        // This works OK
        return this._ObjectSet.Include(include).Where(predicate);
    }

    public IQueryable<T> FindBy(System.Linq.Expressions.Expression<Func<T, bool>> predicate, param string[] include)
    {
        // This will not work but is what I am trying to do
        return this._ObjectSet.Include(include).Where(predicate);
    }
}

Answer 1

You can chain your includes:

public IQueryable<T> FindBy(System.Linq.Expressions.Expression<Func<T, bool>> predicate, param string[] include)
{
    IQueryable<T> query = this._ObjectSet;
    foreach(string inc in include)
    {
       query = query.Include(inc);
    }

    return query.Where(predicate);
}