[dba-VB] OT: VB.Net - general questions

Thanks, I'll read it.

John W. Colby
www.colbyconsulting.com

  -----Original Message-----
  From: dba-vb-bounces at databaseadvisors.com
[mailto:dba-vb-bounces at databaseadvisors.com]On Behalf Of Gary Ray
  Sent: Tuesday, July 15, 2003 3:10 PM
  To: dba-vb at databaseadvisors.com
  Subject: Re: [dba-VB] OT: VB.Net - general questions


  John,

  Take a look at this article:

  http://www.vbdotnetheaven.com/Code/Apr2003/009.asp

  Basically, the System object exposes an Exception object that many of the
other framework classes extend.  I am not sure if there is a named object
for a "missing collection exception", but if you look at the article it
explains how to hande the select case type of exception traps that you are
talking about.


  Gary Ray - Application Developer
  Workforce Information Systems R & D
  E-Mail gray at utah.gov

  >>> jcolby at colbyconsulting.com 07/14/03 12:16PM >>>
  I am porting my SysVars class to VB.Net just as an exercise.  Of course I
  use the error handler insertion wizard for Access, but VB.Net has the new
  Try/catch error handling (which I very much like BTW).  But it does mean
  that no port is trivial since I have to remove all the OnError / resume
kind
  of stuff in every function.

  In my old code I have a case statement where I accumulated the various
  errors that could occur, and once handled a resume next would take me back
  into the code.  that obviously has to change but I'm a little confused as
to
  what it will change to.  For example I have code that attempts to add an
  object to a collection:

      mcolObjNames.Add(strObjName, strObjName)

  There could be two problems here, the first is that no collection has been
  instantiated yet, the second is that the object is already in the
  collection.  Thus a select case would be nice, which was how the old error
  handler in Access worked.

  Select case err
      case XXX
      case YYY
      Case else
  end select

  Now we have:

  Try

      mcolObjNames.Add(strObjName, strObjName)

  Catch e as XXXX (FIRST PROBLEM - WHAT IS xxxx?)
      Handle error here
  Finally

  End Try

  It certainly looks like e could be used in a select case statement.
However
  to do so I need the equivalent of the "resume next".


  AND FINALLY...

  In access I also used a label for the exit such that all exiting code
could
  go through the exit point for cleanup of pointers etc.  The books I have
  don't ever show such a construct.


  John W. Colby
  www.colbyconsulting.com


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