> Hi, all.
>
> I've never been any good at handling exceptions... So I need your
> help.
>
> Within a try{ } block, I have to call a function that has to throw its
> own exception. How should I go about doing this?
>
> try {
>     checkNullHeader( sHeader, ref status );
>     // ...
> }
>
> // ...
>
> // definition of checkNullHeader
> void checkNullHeader( AuthHeader sHeader, ref status status )
> {
>     // if token is null or empty, do not even try to authenticate
>     if( sHeader == null || sHeader.Token == null ||
> sHeader.Token.Equals( "" ) )
>     {
>         try {
>             status.Code = Status.StatusCode.UNAUTHORIZED;
>             status.Description = "Unauthorized";
>             throw new Exception( "Unauthorized" );
>         }
>         catch( Exception e )
>         {
>             Console.WriteLine( "Exception caught here:" + e.ToString ( ) );
>         }
>     }
> }
>
> Is something like this legal? Am I even throwing the exception
> correctly? (Seriously. Exceptions are very foreign to me.) Help me!

> Allie wrote:
> > Hi, all.
>
> > I've never been any good at handling exceptions... So I need your
> > help.
>
> > Within a try{ } block, I have to call a function that has to throw its
> > own exception. How should I go about doing this?
>
> > try {
> >    checkNullHeader( sHeader, ref status );
> >    // ...
> > }
>
> > // ...
>
> > // definition of checkNullHeader
> > void checkNullHeader( AuthHeader sHeader, ref status status )
> > {
> >    // if token is null or empty, do not even try to authenticate
> >    if( sHeader == null || sHeader.Token == null ||
> > sHeader.Token.Equals( "" ) )
> >    {
> >            try {
> >                    status.Code = Status.StatusCode.UNAUTHORIZED;
> >                    status.Description = "Unauthorized";
> >                    throw new Exception( "Unauthorized" );
> >            }
> >            catch( Exception e )
> >            {
> >                    Console.WriteLine( "Exception caught here:" + e.ToString ( ) );
> >            }
> >    }
> > }
>
> > Is something like this legal? Am I even throwing the exception
> > correctly? (Seriously. Exceptions are very foreign to me.) Help me!
>
> Since you are catching the exception thrown within checkNullHeader in
> that same function, your outside call will not see the "Unauthorized"
> exception.  If you simply want to log the "Unauthorized" condition
> (you're already setting a status code and description so the caller to
> checkNullHeader can inspect those to determine the action to take, the
> throwing/catching of an exception with checkNullHeader is a waste.
>
> Can you better define your design?
> --
> Tom Porterfield

>
> So if this function (checkNullHeader) is defined within the try{ }
> block of a particular class, it does not need to throw/catch an
> exception? (Is it OK to leave throw new Exception( "Unauthorized" );
> in the function?)
>
> What if I want to access checkNullHeader from other classes... and/or
> not necessarily from within a try{ } block? Will a try-catch block
> within checkNullHeader make sense then?
>
> An exception needs to be thrown because, while the code and
> description of the status are changing, the calling function is not
> using this data to determine a course of action. If the user is not
> authorized, the rest of the function should not execute. At least,
> that's how I understand it. (I did not write the code. My job is to
> take
>
> if( sHeader == null || sHeader.Token == null ||
> sHeader.Token.Equals( "" ) ) {
> ...
> }
>
> and turn it into a function, as it is used in a lot of other
> functions.)