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Posted 20 Sep 2007


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Open Source QRCode Library

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4.92/5 (145 votes)
20 Sep 2007CPOL1 min read
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

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.

Comments and Discussions

GeneralRe: Fix BUG Pin
Kiki Ariady Putra30-Apr-12 3:21
MemberKiki Ariady Putra30-Apr-12 3:21 
GeneralRe: Fix BUG Pin
Qui Tran19-Jul-12 0:28
MemberQui Tran19-Jul-12 0:28 
GeneralRe: Fix BUG Pin
dhaval_shah_IT26-Jul-12 19:19
Memberdhaval_shah_IT26-Jul-12 19:19 
QuestionCode doesn't work (not compilable) Pin
vadim30714-Apr-12 2:49
Membervadim30714-Apr-12 2:49 
QuestionCode with changes committed to google code Pin
hjgode15-Mar-12 1:33
Memberhjgode15-Mar-12 1:33 
QuestionRe: Code with changes committed to google code Pin
sfitzge30812-Apr-12 4:26
Membersfitzge30812-Apr-12 4:26 
AnswerRe: Code with changes committed to google code Pin
hjgode12-Apr-12 8:22
Memberhjgode12-Apr-12 8:22 
GeneralMy vote of 5 Pin
Nasenbaaer14-Mar-12 16:43
MemberNasenbaaer14-Mar-12 16:43 
QuestionMessage Closed Pin
12-Mar-12 6:39
MemberWebMaster12-Mar-12 6:39 
QuestionIndex was outside the bounds of the array Pin
LaunaSere11-Mar-12 8:49
MemberLaunaSere11-Mar-12 8:49 
AnswerRe: Index was outside the bounds of the array Pin
hjgode13-Mar-12 0:57
Memberhjgode13-Mar-12 0:57 
GeneralRe: Index was outside the bounds of the array Pin
LaunaSere16-Mar-12 6:49
MemberLaunaSere16-Mar-12 6:49 
QuestionMultiple QR Codes Pin
Member 865155520-Feb-12 2:03
MemberMember 865155520-Feb-12 2:03 
Questionthere is problem in ER-encoding/decoding Pin
vvsarma29-Jan-12 17:22
Membervvsarma29-Jan-12 17:22 
SuggestionNew implementation for BCH (15,5) error correction Pin
SergeyKS27-Jan-12 2:43
MemberSergeyKS27-Jan-12 2:43 
BugReed Solomon error correction is not correct Pin
SergeyKS27-Jan-12 2:37
MemberSergeyKS27-Jan-12 2:37 
Questionvisual studio 2010 Pin
Bruno Rezio12-Jan-12 1:36
MemberBruno Rezio12-Jan-12 1:36 
AnswerRe: visual studio 2010 Pin
omar_chavez12-Jan-12 10:00
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AnswerRe: visual studio 2010 Pin
PREMSONBABY22-May-12 23:20
MemberPREMSONBABY22-May-12 23:20 
QuestionImage complexity ?? Pin
Amir1254723-Dec-11 4:56
MemberAmir1254723-Dec-11 4:56 
QuestionGreat code example. How to add image to centre of QR code? Pin
blarney19-Dec-11 9:51
Memberblarney19-Dec-11 9:51 
GeneralGreat work! Pin
Clayton Rumley15-Dec-11 9:41
MemberClayton Rumley15-Dec-11 9:41 
QuestionDecoder not working for character such as: é à Pin
Member 84694668-Dec-11 5:32
MemberMember 84694668-Dec-11 5:32 
Question对中文的支持还是不够! Pin
S.Sams22-Nov-11 21:47
MemberS.Sams22-Nov-11 21:47 
AnswerRe: 对中文的支持还是不够! Pin
Hsing_Yeh20-Dec-11 21:24
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