Should IDataReader::Dispose call IDataReader::Close?

Question

I'm implementing IDataReader and I wonder if the implementation of Dispose is supposed to call Close or not.

Also, should Close call Dispose?

My guess is that Close shouldn't call Dispose and Dispose can call Close since AFAIK you should be able to call Dispose as many times as you want in any object. But this is just a guess and I'd rather hear an expert's opinion.

I just noticed it was IDataReader interface vs the Class sorry SLaks — MethodMan, Dec 16 '11 at 19:34

score 6 · Accepted Answer · answered Dec 16 '11 at 19:29

Close() and Dispose() should do the same thing (one should call the other).
However, Close() does not need to be callable multiple times.

You should inherit the base DbDataReader class instead of re-implementing the whole thing yourself; if so, you'll need to override the abstract Close().

score 1 · Answer 2 · answered Dec 16 '11 at 19:30

.Dispose() should do exactly one thing: release unmanaged resources. Therefore you should call .Close() if and only if calling that function is the correct way to release an unmanaged resource. In this case, I would say that is true (it will release a database connection), and so you should call the function.

score 1 · Answer 3 · answered Dec 16 '11 at 19:31

1

They are both almost the same thing except Close can be called more than 1 time without getting an exception.

If you use the object more than once, implement .Close, if only once, implement .Dispose().

answered Dec 16 '11 at 19:31

SventoryMang

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score -1 · Answer 4 · answered Dec 16 '11 at 19:29

-1

IDataReader is in interface. It doesn't dictate implementation.

answered Dec 16 '11 at 19:29

John Saunders

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How come people write documentation for interfaces then? – Juan Dec 16 '11 at 19:30
Um... In order to document them? – John Saunders Dec 16 '11 at 19:30
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Document what their implementation is supposed to do? – Juan Dec 16 '11 at 19:31
Document what all of their implementations are meant to do. That which is not documented is likely not part of the interface (like whether Dispose must call Close or vice versa) – John Saunders Dec 16 '11 at 19:35

Should IDataReader::Dispose call IDataReader::Close?

4 Answers4