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 Wright's Beginning 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.

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 in VB5.

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 scanner.