My name is Pete Draigh. I work for a regional auditing company and do all of our software and data-driven web development using mostly SQL Server, ASP, and a little Access. This article is about a solution I worked out to dynamically generate a bar code based on the value of an ID field in a database. It would be useful in a situation where users need to enter information into a system, be presented with a summary 'this-is-what-you-entered' page that they can then print and can be tracked later with the barcode. Similar to what many shipping companies such as Fedex use when you use their program to generate an airbill. I'd welcome any feedback at pdraigh@businessstrategy.com.
The problem was to translate a value such as '123456' into a barcode. We use the Code 39 barcode for several things we do at our company. I wanted to put that barcode on a web page so that the user could print out a web page containing that barcode and later, we could use that barcode in the indexing process in our imaging system. Most users have a Code 39 font installed on their system for other purposes, but I didn't want to rely on them having it. I wanted to generate it in the web page and have that be independent of the browser/client computer, etc.
My solution was to create GIF files for each supported character in the the Code 39 set. I got a sample for each character and then I created each character and tested it with our scanner software to make sure it was interpreted correctly. Then to represent the database value as a barcode in my ASP page, I simply loop through each character in the field value with an <IMG SRC="..."> tag to replace the character with the character's bar code GIF. Simple, and doesn't require anything on the client machine.
The code is a simple loop:
Response.write "<IMG SRC=""asterisk.gif"">" 'Code 39 barcodes require an asterisk as the start and stop characters
For x = 1 to len(rst("field1")) response.write "<IMG SRC=""" & mid(rst("field1"),x,1) & ".gif"">" Next
Response.write "<IMG SRC=""asterisk.gif"">"
Make sure you have a GIF for each barcode and you modify the IMG tags for the correct directory, filename, etc. You can also change the WIDTH and HEIGHT attributes of your IMAGE tag to make the barcode display larger or smaller on your page. Not a real complex solution, but sometimes the simpler, the better.
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