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Open Source QRCode Library

, 20 Sep 2007 CPOL
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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

GeneralRe: My vote of 3 PinmemberGaurav.WhiteLotus28-Jun-13 9:46 
QuestionError Pinmemberbebo_s_802-Mar-13 23:47 
GeneralMy vote of 5 PinmemberpeteSJ13-Feb-13 18:41 
QuestionInput string length Pinmemberchrisawoods29-Jan-13 5:37 
AnswerMessage Automatically Removed PinmemberNikeduban26-Mar-13 0:14 
QuestionHow to scan QR Code using Webcam in this library plz help PinmemberRohit Nagbhidkar24-Jan-13 2:30 
Questionqr code library PinmemberTarcode Michael15-Jan-13 16:25 
QuestionOther barcode types PinmemberJBoada3-Jan-13 17:45 
GeneralMy vote of 5 PinmemberJBoada3-Jan-13 17:38 
BugInvalid version in decode PinmemberMember 954616112-Nov-12 12:13 
QuestionRDLC Report PinmemberTintinLille11-Nov-12 1:32 
AnswerMessage Automatically Removed PinmemberNikeduban1-Apr-13 23:35 
QuestionHow to set CorrectionLevel and Version for Encoding? PinmemberMember 94732758-Nov-12 23:34 
QuestionHow to use this? PinmemberMember 94732757-Nov-12 17:30 
Sorry. Kind of a noob here. But this is my last hope for a QR encoder/decoder for Windows Mobile 6.5 / .NET Compact Framework. Any step by step tutorial?
QuestionVersion for Visual Basic 6 (VB6) PinmemberLuigiIT2-Nov-12 23:11 
GeneralMy vote of 5 PinmemberGiovefi18-Oct-12 7:59 
QuestionGreat job Pinmemberanalog99917-Oct-12 7:53 
QuestionNot decoding QR code from scanned Image PinmemberJaydeep Jadav12-Oct-12 21:12 
AnswerRe: Not decoding QR code from scanned Image PinmemberJaydeep Jadav18-Oct-12 20:20 
QuestionUTF8 posing problem. PinmemberAsnarpbio2-Oct-12 22:27 
Questionwhere is QRVerToDataSize ? Pinmembersteve mettraux27-Sep-12 6:24 
QuestionProject Converted In VS 2010 Gives Build Error Pinmemberaqibsd23-Aug-12 0:46 
AnswerRe: Project Converted In VS 2010 Gives Build Error Pinmembercllamed14-Sep-12 7:37 
QuestionError if Encode more than 124 characters PinmemberVivek Deshmukh13-Aug-12 3:16 
AnswerRe: Error if Encode more than 124 characters PinmembermikeXmas21-Aug-12 20:35 
AnswerRe: Error if Encode more than 124 characters Pinmembersaif.silver21-Dec-12 22:44 
QuestionUsing the ThoughtWorks.QRCode.dll in a C++ application Pinmembersonusudhanshu18-Jul-12 0:57 
QuestionQR Code reader PinmemberCode55811-Jul-12 0:37 
QuestionNice Project - Really Helpful PinmemberMember 57127827-Jul-12 0:18 
QuestionCompile fails PinmemberNanosoft from Global20-Jun-12 19:42 
GeneralMy vote of 4 PinmemberBurak Tunçbilek12-Jun-12 3:45 
QuestionFixed Files - New version at twitts homepage PinmemberMember 86976874-Jun-12 9:21 equivalent Pinmemberevilson28-Apr-12 10:48 
QuestionIndex was outside the bounds of the array Pinmemberskanz27-Apr-12 5:47 
AnswerRe: Index was outside the bounds of the array PinmemberMember 117033111-May-12 18:11 
GeneralRe: Index was outside the bounds of the array Pinmemberrapitoloco6-Aug-12 7:22 
GeneralRe: Index was outside the bounds of the array Pinmembermarkoslo8-Oct-12 9:45 
SuggestionFix BUG Pinmembervadim30714-Apr-12 10:08 
GeneralRe: Fix BUG PinmemberKiki Ariady Putra30-Apr-12 3:21 
GeneralRe: Fix BUG PinmemberQui Tran19-Jul-12 0:28 
GeneralRe: Fix BUG PinmemberMember 768863526-Jul-12 19:19 
QuestionCode doesn't work (not compilable) Pinmembervadim30714-Apr-12 2:49 
QuestionCode with changes committed to google code Pinmemberhjgode15-Mar-12 1:33 
QuestionRe: Code with changes committed to google code Pinmembersfitzge30812-Apr-12 4:26 
AnswerRe: Code with changes committed to google code Pinmemberhjgode12-Apr-12 8:22 
GeneralMy vote of 5 PinmemberNasenbaaer14-Mar-12 16:43 
Questionqr code creation control for PinmemberZacbr12-Mar-12 6:39 
QuestionIndex was outside the bounds of the array PinmemberLaunaSere11-Mar-12 8:49 
AnswerRe: Index was outside the bounds of the array Pinmemberhjgode13-Mar-12 0:57 
GeneralRe: Index was outside the bounds of the array PinmemberLaunaSere16-Mar-12 6:49 

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