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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

SuggestionCode for generating whitespace and border Pin
oware27-Oct-11 8:18
Memberoware27-Oct-11 8:18 
Generalhow to use in C++ Pin
Member 197179630-May-11 2:32
MemberMember 197179630-May-11 2:32 
Generalhow i can make this project in vb6 Pin
ferdiansyah18-May-11 23:05
Memberferdiansyah18-May-11 23:05 
Generalhelp Pin
peterlengos16-May-11 23:53
Memberpeterlengos16-May-11 23:53 
GeneralSOS Pin
peterlengos16-May-11 23:52
Memberpeterlengos16-May-11 23:52 
GeneralRe: SOS Pin
Anders Lybecker19-May-11 4:17
MemberAnders Lybecker19-May-11 4:17 
GeneralHow to use the qrcode library Pin
Jelena Hazlehurst13-May-11 19:07
MemberJelena Hazlehurst13-May-11 19:07 
QuestionIncrease max number of characters to encode Pin
kagearm28-Apr-11 2:42
Memberkagearm28-Apr-11 2:42 
AnswerRe: Increase max number of characters to encode Pin
jeanso14-May-11 18:59
Memberjeanso14-May-11 18:59 
Generaljust wanna say thank you Pin
Humsyong27-Apr-11 17:26
MemberHumsyong27-Apr-11 17:26 
GeneralHow to increase maxDataCodewords? Pin
kagearm20-Apr-11 5:42
Memberkagearm20-Apr-11 5:42 
QuestionNoob trying to get this to work in MS Access Pin
jaqqaj18-Apr-11 13:55
Memberjaqqaj18-Apr-11 13:55 
QuestionDLL size Pin
James Knopp17-Apr-11 23:28
MemberJames Knopp17-Apr-11 23:28 
GeneralMy vote of 5 Pin
washingto21-Mar-11 22:18
Memberwashingto21-Mar-11 22:18 
QuestionHow to encode byte data? Pin
jjdd8821-Mar-11 14:05
Memberjjdd8821-Mar-11 14:05 
GeneralMy vote of 5 Pin
Pavel Vladov16-Mar-11 7:00
MemberPavel Vladov16-Mar-11 7:00 
Generalthanks mate Pin
Member 73616421-Mar-11 10:42
MemberMember 73616421-Mar-11 10:42 
GeneralAPP Web Pin
ruben_zer09-Feb-11 7:40
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GeneralRe: APP Web Pin
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MemberMember 769305021-Feb-11 14:02 
GeneralRe: APP Web Pin
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AnswerRe: APP Web Pin
oware27-Oct-11 8:23
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GeneralRe: APP Web Pin
NinjaCat88!13-Feb-12 6:59
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GeneralRe: APP Web Pin
oware13-Feb-12 8:42
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GeneralRe: APP Web Pin
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GeneralRe: APP Web Pin
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