public virtual T GetSingle(Func <T, bool> where,
                                   params Expression <Func <T, object> >[] navigationProperties)
        {
            T item = null;

            using (var context = new ExcurDbContext())
            {
                IQueryable <T> dbQuery = context.Set <T>();

                foreach (var navProperty in navigationProperties)
                {
                    dbQuery = dbQuery.Include <T, object>(navProperty);
                }
                item = dbQuery
                       .AsNoTracking()
                       .FirstOrDefault(where);
            }
            return(item);
        }
        // now a method with "where"
        public virtual IList <T> GetList(Func <T, bool> where,
                                         params Expression <Func <T, object> >[] navigationProperties)
        {
            List <T> list;

            using (var context = new ExcurDbContext())
            {
                IQueryable <T> dbQuery = context.Set <T>();

                foreach (var navProperty in navigationProperties)
                {
                    dbQuery = dbQuery.Include <T, object>(navProperty);
                }
                list = dbQuery
                       .AsNoTracking()
                       .Where(where)
                       .ToList();
            }
            return(list);
        }
        public virtual IList <T> GetAll(params Expression <Func <T, object> >[] navigationProperties)
        {
            List <T> list;

            // for short living contexts its better to use eager loading
            using (var context = new ExcurDbContext())
            {
                // To implement LINQ-providers to external
                // data let's use the interface IQueryable <T>
                // it doesn't load all set to memory unlike IEnumerable
                IQueryable <T> dbQuery = context.Set <T>();

                // eager loading
                foreach (var navProperty in navigationProperties)
                {
                    dbQuery = dbQuery.Include <T, object>(navProperty);
                }
                list = dbQuery
                       .AsNoTracking() // don't track any changes
                       .ToList();
            }
            return(list);
        }