HTML Help VB/6 Sample Application
Updated December 24, 1999
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This updated sample application, now provided as source-code only,
illustrates almost every capability of the HTML
Help class module. It's similar in operation to my original Case
Study 2, "A Library Transaction Wizard", from Peter
Visual Basic 6 (Wrox Press 1998, ISBN 1-861001-05-3). The
difference is that, in this version, almost every conceivable HTML
Help call is demonstrated.
- For more detailed
information about barcode technology, see Barcode1.
The sample application was created with Visual Basic 5 on a
baseline Windows 95 system with IE 4.01 installed, which also
installs the HTML Help 1.0 viewer. The main issue with Visual Basic
5 is that it hasn't a clue as to what an HTML Help file is. You
can't set the App.HelpFile path to a CHM without getting an error at
runtime, nor can you use any of the standard methods or properties
to set up What's This Help. The Check-Out Wizard's popups are set up
for use in VB6, so they won't work in VB 5. However, the popups on
the Check-In Wizard and the Switchboard are set up so they'll appear
The sample code also works under Visual Basic 6. If the source
code is opened and run in Visual Basic 6, or compiled with it,
What's This Help on the Check-Out form will work just fine. This is
so you can see an example of how this works. However, once you do
this, if the project is saved, it won't open again in Visual Basic 5
without a small fix. You need to open the VBP file in NotePad and
remove the line "RETAINED=0" before it will open in Visual
Basic 5 again.
The check-out process is based on the same process libraries have
been using for a very long time. The process works like this:
- Scan the patron's barcode. In this case, the barcode numbers
in the database are currently between 1 and 14.
- Scan the barcode in the on the item. In this case, the barcode
numbers in the database are currently between 100 and 178.
- Verify the return date.
- Verify all of the information and change the status of the
item. Also, if the patron has more items to check out …
- … have a separate step to scan just the item's barcodes so
the patron's barcode doesn't have to be scanned each time.
- Return to the beginning when complete.
This procedure is also to be used to extend the return date of an
item. In the second step, the item can actually be checked-in
"midstream", and the process continued, without having to
use the check-in procedure first.
The check-in procedure is quite simple:
- Scan the barcode on the item.
- Verify the information. If it's correct, change the item's
status and go back to the beginning.
Both procedures check the item's current status to see if the
correct process is being used.
Note that a barcode scanner is not required for you to use this
sample application. The sample was designed for use with the type of
scanner called a keyboard wedge. This is a small handheld scanner
which connects to the computer via a 'Y' connector which ties in to
the keyboard connection. Both the keyboard and scanner are connected
at the same time. This type of scanner sends the barcode information
to the computer in the form of keyboard data, and can be programmed
to send a simulated Enter keypress at the end of the barcode. The
data pops into whichever control has the focus, the Enter keypress
clicks the default button, and the process continues almost
instantaneously at the next step. The keyboard can also be used to
enter data from damaged or unreadable barcodes. Here, we'll use the
keyboard to enter data since you likely don't have a keyboard wedge