Published: 25 Jun 2007
By: Imran Nathani

In this article we are going to generate barcodes in .NET. Barcode-aware devices, such as scanners and printers, are readily available on the market, as long as the barcodes we generate follow the standards.We will implement barcode generation using Microsoft Ajax in a web application.

Introduction

To most of us, barcodes are a common sight. This is because today barcodes enable delivery and retail systems to perform faster. When programming with older languages, implementing barcodes is difficult. It would need either a set of computer graphics programmers with knowledge of different barcodes standards, or an expensive third party component. But things are different today. With the help of the .NET framework, we will perform the same task in an ASP.NET page with just a few lines of code.

Selecting the Barcode Standard

Barcodes are a pictorial representation of a particular set of information. This information is conveyed through dark colored (normally black) lines of different widths, on any light (normally white) background. For uniform implementation, we have few standards of barcodes, like EAN/UPC, Code 39, Code 128 and so on. Without really understanding the theory behind these standards we just have to decide, as per our requirement, to which standard we want to adhere. With the code presented in this article, any standard can be implemented.

Bar-coding or fonting?

If we search the Internet we can easily come across free font files which implement most barcode standards. Using these font files, we can draw the information string on an image and set the font of that string to the barcode font. This actually reduces the whole task of information bar-coding to simply information fonting. In our example, we will use the file Barcodefont.ttf.

Before we begin

We are going to split the whole procedure into two parts. The first one involves generating the image. The second one discusses image delivery. The image generation consists of drawing the barcode on a canvas and storing it in a file. Regarding image delivery, we consider two options: downloading the image or displaying it directly in a control.

Every font file (.ttf) has a typeface name. Since we need to use it in our code, let’s open the font file and check the typeface name as shown in figure 1.

Figure 1: Checking the typeface name

Also, we need to decide a way to provide a unique name to each file that is generated by different users, in order to avoid resource conflict. In the code, we use the following filename format:

[text to be bar-coded]_[long representation of DateTime.Now].jpg

Therefore, a conflict would arise only if two users try to barcode the same string at the same instant (up to milliseconds).This conflict would be resolved in the next millisecond.

Barcode Image Generation

To generate the image, we first need to import some namespaces related to drawing and file management.The code for generating the image is reported in listing 1.

Listing 1: Code for generating the image

Barcode Image Delivery

Image delivery is about how we want our users to get the generated image. There can be multiple complex ways for image delivery; involving hyperlinks, databases, zipping and so on. We will consider two options:

1) Displaying the image in a control

Here we would display the image directly in an image box on a different page. The path to access the image would be that of an .aspx page with the text to be bar-coded appended to the the query string, like so:

2) Downloading the image.

In this case, we would directly send the file for download by the user. The user actually saves the image file to their hard disk, as shown in the following code:

Cleaning up the code

Despite which image delivery option we choose, an image file is generated on the server. If this file is required in the future, then the following clean up code is not required. However, if these files are not needed, we can write the clean up code just before disposing the response object, like so:

Summary

A wise man once said "Knowledge is my weapon”. This is evident in this case, because of the price of third party bar-coding components on the Internet. For more information on barcodes and barcode standards, check out this Wikipedia entry.

<<  Previous Article Continue reading and see our next or previous articles Next Article >>

About Imran Nathani

Sorry, no bio is available

This author has published 5 articles on DotNetSlackers. View other articles or the complete profile here.

Other articles in this category


Android for .NET Developers - Location and Maps
In Windows Phone and iOS getting the current position of the device in terms of latitude and longitu...
Android for .NET Developers - Using Web Views
In this article, I'll show a native app that contains a web-based view. The great news is that HTML ...
Android for .NET Developers - Building a Twitter Client
In this article, I'll discuss the features and capabilities required by an Android application to ta...
Developing a Hello World Java Application and Deploying it in Windows Azure - Part II
In this article we will see the steps involved in deploying the WAR created in the first part of thi...
Ref and Out (The Inside Story)
Knowing the power of ref and out, a developer will certainly make full use of this feature of parame...

You might also be interested in the following related blog posts


ASP.NET AJAX Release History : Q2 2009 BETA (version 2009.2.616) read more
Are you caching your images and scripts? IIS SEO can tell you read more
Image Transforms with the ASP.NET Generated Image Control read more
Aspose.Total for .NET Q4 2008 Released read more
Deep Zoom Image Generation with DeepZoomTools.DLL read more
ImageDraw 4.0 for ASP.NET now available read more
Silverlight Server Configuration read more
RADactive I-Load 2008.R1 released - Wysiwyg image upload-resize-crop tool read more
Barcode Professional 5.0 for .NET now available read more
Getting Images to render properly in the ASP.NET Designer read more
Top
 
 
 

Discussion


Subject Author Date
placeholder free? Pat Bell 4/9/2013 12:22 AM
Barcode Generation Susan Smith 5/23/2013 10:32 PM
placeholder thank you Ahmed Helmy 7/1/2008 4:44 AM
:: Good One :: Gemini Gemini 2/6/2009 12:56 AM

Please login to rate or to leave a comment.