When you call GetAllAnimals it doesn’t actually execute any code until you enumerate the returned IEnumerable in a foreach loop. The dataContext is being disposed as soon as the wrapper method returns, before you enumerate the IEnumerable. The simplest solution would be to make the wrapper method an iterator as well, like this: public static … Read more
Yes, go for it. Although some people think IDisposable is implemented only for unmanaged resources, this is not the case – unmanaged resources just happens to be the biggest win, and most obvious reason to implement it. I think its acquired this idea because people couldn’t think of any other reason to use it. Its … Read more
The Framework Design Guidelines (2nd ed) has this as (ยง9.4.1): AVOID throwing an exception from within Dispose(bool) except under critical situations where the containing process has been corrupted (leaks, inconsistent shared state, etc.). Commentary [Edit]: There are guidelines, not hard rules. And this is an “AVOID” not a “DO NOT” guideline. As noted (in comments) … Read more
You should be safe to call it more than once, though you should probably avoid it if you can. From the MSDN page on IDisposable.Dispose(): If an object’s Dispose method is called more than once, the object must ignore all calls after the first one. The object must not throw an exception if its Dispose … Read more
I believe the recommended practice is to throw the following: throw new ObjectDisposedException(GetType().FullName); Or including the check, these two lines of code at the top of each method that needs it (obviously not the Dispose method itself): if (this.disposed) throw new ObjectDisposedException(GetType().FullName); Might even be helpful to refactor this into a tiny method for usability.
There are only 2 reasons for implementing IDisposable on a type The type contains native resources which must be freed when the type is no longer used The type contains fields of type IDisposable If neither of these are true then don’t implement IDisposable EDIT Several people have mentioned that IDisposable is a nice way … Read more
Yes, foreach will call Dispose() on the enumerator if it implements IDisposable.
using is basically the equivalent of: try { // code } finally { obj.Dispose(); } So it also has the benefit of calling Dispose() even if an unhandled exception is thrown in the code within the block.
So it seems like the calling code needs to know about and take ownership of the response message as well as the stream, or I leave the response message undisposed and let the finalizer deal with it. Neither option feels right. In this specific case, there are no finalizers. Neither HttpResponseMessage or HttpRequestMessage implement a … Read more
P.S.: I have posted a new answer (containing a simple set of rules who should call Dispose, and how to design an API that deals with IDisposable objects). While the present answer contains valuable ideas, I have come to believe that its main suggestion often won’t work in practice: Hiding away IDisposable objects in “coarser-grained” … Read more