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Open Source QRCode Library

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20 Sep 2007CPOL1 min read 6M   192.3K   421   334
How to use QRCode library to encode and decode QRCode
Screenshot - qrcode_app_decode.jpg

Introduction

In this article, I will briefly describe the functionalities of the QRCode library.

Background

QRCode library is a .NET component that can be used to encode and decode QRCode. QRCode is a 2 dimensional bar code that originated in Japan. Nowadays, it is widely used in a wide range of industries, e.g. for vehicle parts tracking and inventory management.

QR stands for "Quick Response". It was created by the Japanese corporation Denso-Wave in 1994 and is aimed at decoding contents at high speed. Nowadays, QR Code is used in mobile phones to ease data entry.

QRCode can also be printed on a business card or shown on any display, which can then be captured by the mobile phone provided the mobile phone has the software to read QRCode.

QRCode library provides functions to:

  1. Encode content into a QR Code image which can be saved in JPEG, GIF, PNG, or Bitmap formats
  2. Decode a QR Code image

Using the Code

The library can be used in any .NET 2.0 Windows Application, ASP.NET Web application or Windows Mobile device application.

Some sample screenshots are displayed below:

Screenshot - qrcode_app_encode.jpg

Screenshot - qrcode_mobile_encode.jpg

C#
QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
          String encoding = cboEncoding.Text ;
          if (encoding == "Byte") {
              qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
          } else if (encoding == "AlphaNumeric") {
              qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.ALPHA_NUMERIC;
          } else if (encoding == "Numeric") {
              qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.NUMERIC;
          }
          try {
              int scale = Convert.ToInt16(txtSize.Text);
              qrCodeEncoder.QRCodeScale = scale;
          } catch (Exception ex) {
              MessageBox.Show("Invalid size!");
              return;
          }
          try {
              int version = Convert.ToInt16(cboVersion.Text) ;
              qrCodeEncoder.QRCodeVersion = version;
          } catch (Exception ex) {
              MessageBox.Show("Invalid version !");
          }

          string errorCorrect = cboCorrectionLevel.Text;
          if (errorCorrect == "L")
              qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.L;
          else if (errorCorrect == "M")
              qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;
          else if (errorCorrect == "Q")
              qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.Q;
          else if (errorCorrect == "H")
              qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.H;

          Image image;
          String data = txtEncodeData.Text;
          image = qrCodeEncoder.Encode(data);
          picEncode.Image = image;

History

  • 20th September, 2007: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Software Developer (Senior)
Malaysia Malaysia
A programmer for a long time, and still learning everyday.

A supporter for open source solutions, and have written quite a few open source software both in .NET and Java.

https://mengwangk.github.io/

Comments and Discussions

 
GeneralThis is exact what i need, thanks Pin
Xiaosheng Wang30-Jun-10 5:14
Xiaosheng Wang30-Jun-10 5:14 
GeneralExcellent !!! Pin
Al Rice23-Jun-10 15:31
Al Rice23-Jun-10 15:31 
QuestionRS decoder not working? Pin
davb30046-Jun-10 1:31
davb30046-Jun-10 1:31 
AnswerRe: RS decoder not working? Pin
Scootty9-Jun-10 22:32
Scootty9-Jun-10 22:32 
GeneralRe: RS decoder not working? Pin
WashCaps5-Aug-10 7:23
WashCaps5-Aug-10 7:23 
General!!!!!!!!HELP!!!!!!!!!!!!!!! Pin
ssnv.girish19-May-10 23:19
ssnv.girish19-May-10 23:19 
GeneralHelp About Resource Files Pin
ssnv.girish19-May-10 23:17
ssnv.girish19-May-10 23:17 
GeneralYES! Thank you!(!) Simple windows program to read / decode QR code - Zoinks! Pin
unRheal23-Apr-10 14:35
unRheal23-Apr-10 14:35 
Sweet.

I just spent half a freaking hour (or maybe more like an hour..) looking for a simple Windows program that would take a QR Code image and decode it! (free / freeware - I don't wanna spend $2000 to decode a few QR Code images!) Wink | ;)

I finally Googled "windows freeware read decode qr code" and your CodeProject (one of my Fav sites, stupid I didn't think to just look here sooner!) project came out on top. Many previous Google searches in vain! Frown | :(

This did exactly what I want - even though for you it was just an example app, it's perfect!

Can't say Thank You enough - and now I even have code to do it if I ever want to put it into a project myself as well.

Totally awesome, and many, many thanks!

Cheers!
GeneralJust want to say thank you Pin
Member 39749963-Apr-10 12:59
Member 39749963-Apr-10 12:59 
GeneralEcode/decode VCard Info Pin
rohit_bciit31-Jan-10 3:44
rohit_bciit31-Jan-10 3:44 
AnswerRe: Ecode/decode VCard Info [modified] Pin
Nismoto10-Mar-10 15:52
Nismoto10-Mar-10 15:52 
General'ThoughtWorks.QRCode.Properties.Resources' does not contain a definition for 'GetResource' Pin
wcwong220-Jan-10 5:15
wcwong220-Jan-10 5:15 
GeneralRe: 'ThoughtWorks.QRCode.Properties.Resources' does not contain a definition for 'GetResource' Pin
Member 308832518-Mar-10 5:30
Member 308832518-Mar-10 5:30 
GeneralRe: 'ThoughtWorks.QRCode.Properties.Resources' does not contain a definition for 'GetResource' Pin
mwhouser26-Mar-10 7:19
mwhouser26-Mar-10 7:19 
GeneralRe: 'ThoughtWorks.QRCode.Properties.Resources' does not contain a definition for 'GetResource' Pin
king'ori16-Mar-11 19:00
king'ori16-Mar-11 19:00 
GeneralRe: 'ThoughtWorks.QRCode.Properties.Resources' does not contain a definition for 'GetResource' Pin
Deacon Frost2017-Jun-11 11:08
Deacon Frost2017-Jun-11 11:08 
GeneralTesting the application Pin
classic1215-Jan-10 2:13
classic1215-Jan-10 2:13 
GeneralRe: Testing the application Pin
KillaW0lf0413-Jul-10 3:04
KillaW0lf0413-Jul-10 3:04 
Questiondrcode.dll Pin
dodi catur susilo7-Jan-10 19:16
dodi catur susilo7-Jan-10 19:16 
QuestionCan anyone make this application for vb.net??? Pin
bl3ck_id15-Dec-09 5:10
bl3ck_id15-Dec-09 5:10 
AnswerRe: Can anyone make this application for vb.net??? Pin
Member 149466623-Jul-10 2:21
Member 149466623-Jul-10 2:21 
GeneralRe: Can anyone make this application for vb.net??? Pin
d lowey26-Mar-11 16:38
d lowey26-Mar-11 16:38 
GeneralNeed Help Pin
bl3ck_id9-Dec-09 5:28
bl3ck_id9-Dec-09 5:28 
GeneralLibrary Pin
mycronichead11-Oct-09 17:17
mycronichead11-Oct-09 17:17 
GeneralInvalid number of find pattern detected Error when decoding qr code version 5 and size 2 correction level Musing Pin
hamletj8-Oct-09 20:32
hamletj8-Oct-09 20:32 

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