Let's say I have a dictionary where all the values are strings. Does
anyone know if it is faster to say:

dim s as string = directcast(_dictionary(key), string)

or

dim s as string = _dictionary(key).ToString()

One of the nice things about using .ToString on an object reference is
when working with a db. You know the column is char or varchar, but if
it is nullable, the underlying type could be a DBNULL or string.
Calling .ToString() on a DBNULL returns "", which is an acceptable
response in most situations.

Thanks,
Eric Marvets
MVP - Visual Developer, Security

toString is implemented in an optimized way in the framework, it should be
faster than the overhead of directcast

<emarvets (AT) gmail (DOT) com> wrote

How is it different than any other virtual method? I guess the real
question I should have posed is if it's quicker to call a virtual
method or cast to the concrete version from a pure performance
standpoint?

-Eric Marvets
MVP - Visual Developer, Security

<emarvets (AT) gmail (DOT) com> wrote:
Either way, the cost of looking the key up in the dictionary (which is
fairly fast in itself) is likely to dwarf the cost of either the cast
or the call to ToString. I find it very unlikely that you'll see any
significant performance difference at all. Use the version which is
most convenient/readable for you.

--
Jon Skeet - <skeet (AT) pobox (DOT) com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
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