> Hi there,
>
> I have my own "way" I guess of coding, like we all do, whilst I try to
> maintain consistency throughout my own applications I often wonder whether
> there are better ways of doing things...since I started using Visual Studio
> 2005 I've been quite pleased with the messages it gives you when you make
> mistakes, and its underlining of unused variables and so on...
>
> One thing that, not so much puzzles me, but makes me think over and over
> again is the "unused variables"....here's an example..
>
> ' exception handling
> Try
>
> ' instantiate
> sqlCommand = GetSQLCommand()
>
> ' set command properties
> sqlCommand.CommandText = commandText
> sqlCommand.CommandType = commandType
> sqlCommand.Connection = sqlConnection
>
> ' iterate
> For iteration = 0 To (parameters.Count - 1)
>
> ' add parameter
> sqlCommand.Parameters.Add(parameters(iteration))
>
> Next
>
> Catch ex As Exception
>
> ' housekeeping
> Dispose(sqlCommand)
> Dispose(sqlConnection)
>
> ' TODO: Unable to set command properties
>
> End Try
>
> In the above example, Visual Studio unlines the "sqlCommand" in the
> housekeeping section - Dispose(sqlCommand) - because it believes that it
> could well be "null" and might throw and exception (null reference
> exception)...
>
> Now, I know it wont(shouldn't!), because in order to get into the "Catch"
> part of the exception handling it would have to have begun in the "Try"
> section, and in there I create a new instance of the object. I guess there
> could be something, not that I know what, but something that might prevent
> the object from being created, and therefore I can see why it does
> this...however, in my Dispose function I also have code which checks to see
> if the object exists before trying to do anything else with it...
>
> Please note that this is just one example out of many in my project where I
> use exception handling, but the query is the same with all - what I'm
> wondering is whether there's a way that I can "satisfy" Visual Studio so that
> it ignores this "problem" etc. The only way I can see is to create the
> object outside of the "Try", but that kinda defeats the point....
>
> Any info on this would be appreciated, I'm sure we all have our different
> ways of doing things and I'd like to see if anyone else does things similar
> or completely different to me. I also appreciate that these are only
> "warnings" and wont necessarily cause me a load of grief if I have taken them
> into account - just a case of a developer trying to be tidy I guess...
>
> Cheers
>
> Rob
Theoretically, your GetSQLCommand() could have thrown the exception. In
that case the assignment to sqlCommand did not happen when control
reached the Catch, so it will be null there ...
Hans Kesting
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