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Any seasoned Visual Basic 6 programmer
who has picked up a Pocket PC and spent any more than 15
minutes playing with embedded Visual Basic will be quite
vocal in pointing out that eVB just doesn't want to do what
you want to do. Innovative Decision Support Systems (IDSS)
has come to our rescue with IDSSAAPPII, a library of functions
guaranteed to solve the most common problems VB6 programmers
find when transitioning to eVB.
Among the long list of capabilities
that IDSSAPI provides are playing sound files, running other
programs, getting and setting the system time, pausing code
execution, run other programs, perform a soft reset, enhancing
the functionality of list boxes, examining and manipulating
memory allocation, accessing battery power statistics, getting
and setting registry values, removing screen elements (such
as the Start button, SIP menu, and task bar), and responding
to hardware keys. For a complete and up to date list of
features, you will want to take a look at the IDSSAPI
web site [http://www.innovativedss.com/idssapi.asp].
Later in this article we will see how to explore the innards
of this library by using the Object Browser Tool.
IDSSAPI is essentially a "wrapper"
for the Windows CE Application Programming Interface (API),
giving eVB developers access to advanced functionality that
could otherwise only be achieved by learning eVC++ or using
sophisticated routines and "hacks" to access the
WinCE API directly from eVB. The purpose of a "wrapper"
(be it IDSSAPI or any other wrapper for any other language)
is to provide simplified ways of performing certain tasks
that would otherwise be relatively difficult. The inherent
problem thus associated with wrappers is that by simplifying
a task, they must sacrifice the flexibility that could be
achieved by taking the more complex direct approach. IDSSAPI
is, by definition, a victim of this law of nature.
One example of this is IDSSAPI's PlaySound
method which takes a single parameter: the filename of an
sound file to play. This is very straightforward and common
sense would dictate that it is sufficient. Meanwhile, the
WinCE API's equivalent function is significantly more difficult
to use but this is due in part to the added options it provides
such as the ability to choose whether or not to play the
sound synchronously, asynchronously, looped, etc. [Note
that you can see this for yourself by looking at lines #238-243
of the "mmsystem.h" file that comes with Microsoft's
Embedded Visual Tools.]
If your needs require advanced
functionality and tighter control over the program, directly
accessing the WinCE API remains to be the only way to go.
If you're looking for a low cost method to perform tasks
that would otherwise be involve complex interaction with
the WinCE API, then IDSSAPI is an excellent solution which
supports the key selling points of VB as a language (simplified
coding syntax/style and fast development cycles).
Once you've decided that IDSSAPI is
something you want to use and have installed it on your
desktop, you will need to create a reference to it in your
eVB.
To do this, select "References."
from the eVB's "Project" menu. Note that if IDSSAPI
does not appear in the list of references to choose from,
you will need to click the "Browse." button and
manually find the idssapi.tlb file, ignoring the message
box saying that IDSSAPI was not designed for your platform.
Now, check the box labeled "IDSS Windows CE API Wrapper
Function Library" and you're good to go.
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