Question

Is it reasonable to make a rule against explicitly calling Dispose() on an IDisposable object?

Are there any cases where a using statement cannot properly ensure an IDisposable object is cleaned up?

Answer 1

Is it reasonable to make a rule against explicitly calling Dispose() on an IDisposable object?

No.

Are there any cases where a using statement cannot properly ensure an IDisposable object is cleaned up?

There are certainly cases where it makes no sense to use using to dispose an object for you. For example, all cases where the desired lifetime of the object is not bound by a particular activation of a method containing a using statement.

Consider for example a disposable object which “takes over management” of another disposable object. The “outer” object may well be disposed by a using block, but how is the “inner” object, likely stored in a private field of the outer object, to be disposed without an explicit call to Dispose()?