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Open Source QRCode Library

, 20 Sep 2007
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How to use QRCode library to encode and decode QRCode
Screenshot - qrcode_app_decode.jpg


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


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

  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!");
            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;


  • 20th September, 2007: Initial post


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


About the Author

Web Developer
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.

Comments and Discussions

QuestionProject Converted In VS 2010 Gives Build Error Pinmemberaqibsd22-Aug-12 23:46 
AnswerRe: Project Converted In VS 2010 Gives Build Error Pinmembercllamed14-Sep-12 6:37 
QuestionError if Encode more than 124 characters PinmemberVivek Deshmukh13-Aug-12 2:16 
AnswerRe: Error if Encode more than 124 characters PinmembermikeXmas21-Aug-12 19:35 
AnswerRe: Error if Encode more than 124 characters Pinmembersaif.silver21-Dec-12 21:44 
QuestionUsing the ThoughtWorks.QRCode.dll in a C++ application Pinmembersonusudhanshu17-Jul-12 23:57 
QuestionQR Code reader PinmemberCode55810-Jul-12 23:37 
QuestionNice Project - Really Helpful PinmemberMember 57127826-Jul-12 23:18 
Dear Twit88
The project was well thought out and had good capabilities for use with QR codes. I had some issues loading the project from the code project page. However, was able to get it running when i downloaded from the Google Web site.
Excellent work..
QuestionCompile fails PinmemberNanosoft from Global20-Jun-12 18:42 
GeneralMy vote of 4 PinmemberBurak Tunçbilek12-Jun-12 2:45 
QuestionFixed Files - New version at twitts homepage PinmemberMember 86976874-Jun-12 8:21 equivalent Pinmemberevilson28-Apr-12 9:48 
QuestionIndex was outside the bounds of the array Pinmemberskanz27-Apr-12 4:47 
AnswerRe: Index was outside the bounds of the array PinmemberMember 117033111-May-12 17:11 
GeneralRe: Index was outside the bounds of the array Pinmemberrapitoloco6-Aug-12 6:22 
GeneralRe: Index was outside the bounds of the array Pinmembermarkoslo8-Oct-12 8:45 
SuggestionFix BUG Pinmembervadim30714-Apr-12 9:08 
GeneralRe: Fix BUG PinmemberKiki Ariady Putra30-Apr-12 2:21 
GeneralRe: Fix BUG PinmemberQui Tran18-Jul-12 23:28 
GeneralRe: Fix BUG PinmemberMember 768863526-Jul-12 18:19 
QuestionCode doesn't work (not compilable) Pinmembervadim30714-Apr-12 1:49 
QuestionCode with changes committed to google code Pinmemberhjgode15-Mar-12 0:33 
QuestionRe: Code with changes committed to google code Pinmembersfitzge30812-Apr-12 3:26 
AnswerRe: Code with changes committed to google code Pinmemberhjgode12-Apr-12 7:22 
GeneralMy vote of 5 PinmemberNasenbaaer14-Mar-12 15:43 

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