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Open Source QRCode Library

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4.92 (142 votes)
20 Sep 2007CPOL
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: Some Errors and functionality not working - Fixed for Developer Studio 2012 Pin
Member 1099764310-Apr-15 2:59
MemberMember 1099764310-Apr-15 2:59 
GeneralRe: Some Errors and functionality not working - Fixed for Developer Studio 2012 Pin
Mario Gluscic17-Apr-15 15:35
MemberMario Gluscic17-Apr-15 15:35 
AnswerRe: Some Errors and functionality not working - Fixed for Developer Studio 2012 Pin
Cypher72017-Apr-15 11:05
MemberCypher72017-Apr-15 11:05 
GeneralRe: Some Errors and functionality not working - Fixed for Developer Studio 2012 Pin
Mario Gluscic17-Apr-15 15:35
MemberMario Gluscic17-Apr-15 15:35 
AnswerRe: Some Errors and functionality not working - Fixed for Developer Studio 2012 Pin
Member 1201398726-Sep-15 18:06
MemberMember 1201398726-Sep-15 18:06 
Questionfile is being used by another process, attempting to rename Pin
d200520-Feb-15 7:22
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QuestionOne question regarding Data store Pin
Tridip Bhattacharjee11-Feb-15 1:46
professionalTridip Bhattacharjee11-Feb-15 1:46 
Generalrequest Pin
Member 1130541314-Dec-14 23:33
MemberMember 1130541314-Dec-14 23:33 
Questionlittle code change to support Chinese string Pin
DavidGzp29-Nov-14 12:14
MemberDavidGzp29-Nov-14 12:14 
Questionbug for a particular string Pin
msilenius122-Oct-14 19:55
Membermsilenius122-Oct-14 19:55 
QuestionNICE!! Pin
mithunmf11-Oct-14 5:28
Membermithunmf11-Oct-14 5:28 
QuestionExcellent Pin
Member 1109038217-Sep-14 14:48
MemberMember 1109038217-Sep-14 14:48 
Questiongreat Pin
Moonaly24-Aug-14 20:45
MemberMoonaly24-Aug-14 20:45 
GeneralExcellent work, 2 thumbs up Pin
deaironi25-Jul-14 21:21
Memberdeaironi25-Jul-14 21:21 
QuestionSolution to encode and decode Unicode Pin
Budsy29-Mar-14 21:08
MemberBudsy29-Mar-14 21:08 
AnswerRe: Solution to encode and decode Unicode Pin
MuhammadUSman121-Aug-14 22:56
MemberMuhammadUSman121-Aug-14 22:56 
QuestionTry to encode the error QR image Pin
vknguyen199213-Mar-14 1:22
Membervknguyen199213-Mar-14 1:22 
QuestionA good effort but no longer works Pin
replaysMike7-Mar-14 21:20
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QuestionCyrillic Pin
Shaitan-Babay4-Mar-14 23:24
MemberShaitan-Babay4-Mar-14 23:24 
QuestionError Pin
lbdalmendray13-Feb-14 8:32
Memberlbdalmendray13-Feb-14 8:32 
AnswerRe: Error Pin
Member 1061825325-Feb-14 0:01
MemberMember 1061825325-Feb-14 0:01 
AnswerRe: Error Pin
atlaste27-Feb-14 1:16
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QuestionProblem in Run Pin
somayyeh.taheri3-Feb-14 2:52
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QuestionRe: Problem in Run Pin
nguyenquocbinh30-Sep-16 1:11
Membernguyenquocbinh30-Sep-16 1:11 
QuestionReally great! Pin
Member 79212685-Dec-13 23:32
MemberMember 79212685-Dec-13 23:32 

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Posted 20 Sep 2007


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