.NET Entity Framework - IEnumerable VS. IQueryable

Question

Please see this line of code. This is an invocation of a stored procedure, which returns an ObjectResult. In order to extract the long values I add

Answer 1

IEnumerable will not hydrate until materialized. If calling a stored procedure I would think that there is no further filter required, I mean you send parameters to a stored procedure to produce the desired subset of data returned. IEnumerable tied to a stored procedure is fine. However if you are fetching the entire contents of a table, then filtering in the application you should have a strategy. Like, do not ToList() the IEnumerable of the table, you will materialize all rows. Sometimes this will cause an out of memory exception. Besides why consume memory without reason. Use IQueryable against the context, that way you can filter the table at the Data Source, and not in the application. In answer, you have to materialize it. IEnumerable is an interface, only materializing it will "initialize" its type and produce something in my understanding.