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Posted 20 Sep 2007

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

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.

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Comments and Discussions

QuestionIndexOutOfRangeException Pin
debbieboy2k30-Aug-17 6:18
memberdebbieboy2k30-Aug-17 6:18 
QuestionRegrading QR Code Genereator Pin
Member 1306301018-May-17 2:52
memberMember 1306301018-May-17 2:52 
Questionhelp Pin
Member 123410598-Mar-17 1:08
memberMember 123410598-Mar-17 1:08 
Questionopen source dll is not working in SSRS Pin
Member 1278240710-Oct-16 19:16
memberMember 1278240710-Oct-16 19:16 
Question[My vote of 1] Huge Lib for generating a QR code? Pin
Alphons van der Heijden23-Jun-16 0:56
professionalAlphons van der Heijden23-Jun-16 0:56 
QuestionData Matrix Pin
Umair Tariq31-May-16 20:29
memberUmair Tariq31-May-16 20:29 
QuestionQRCode App Not working for tilted qr codes Pin
gaurav baluni4-Apr-16 0:50
membergaurav baluni4-Apr-16 0:50 
QuestionError in Line 454 of QRCodeEncoder Pin
Member 1140851412-Feb-16 0:36
memberMember 1140851412-Feb-16 0:36 
AnswerRe: Error in Line 454 of QRCodeEncoder Pin
Member 1140851412-Feb-16 2:42
memberMember 1140851412-Feb-16 2:42 
GeneralRe: Error in Line 454 of QRCodeEncoder Pin
Tachyonx16-Jun-16 1:57
memberTachyonx16-Jun-16 1:57 
GeneralMy vote of 3 Pin
Brady Kelly29-Dec-15 5:11
memberBrady Kelly29-Dec-15 5:11 
QuestionVery bad coding Pin
Brady Kelly29-Dec-15 5:10
memberBrady Kelly29-Dec-15 5:10 
PraiseWorks Great Pin
BlackstormSP15-Dec-15 0:47
memberBlackstormSP15-Dec-15 0:47 
QuestionHelp me? Pin
Pai Soe6-Dec-15 22:11
memberPai Soe6-Dec-15 22:11 
QuestionCould not able to use dll in windows mobile Pin
Anil Kumar R.30-Nov-15 1:50
memberAnil Kumar R.30-Nov-15 1:50 
QuestionIs it possible to display the image in web browser? Pin
PhyxeTernida7-Oct-15 23:47
professionalPhyxeTernida7-Oct-15 23:47 
AnswerRe: Is it possible to display the image in web browser? Pin
Member 889549513-Nov-15 6:39
memberMember 889549513-Nov-15 6:39 
QuestionRegarding QR Barcode Pin
simantamedhi29-Jul-15 20:41
membersimantamedhi29-Jul-15 20:41 
Questionhao li haide yangzi Pin
Member 1183258212-Jul-15 21:48
memberMember 1183258212-Jul-15 21:48 
AnswerRe: hao li haide yangzi Pin
linqing17128-Nov-16 20:12
memberlinqing17128-Nov-16 20:12 
GeneralMy vote of 5 Pin
RedDk18-Jun-15 10:39
memberRedDk18-Jun-15 10:39 
GeneralMy vote of 1 Pin
RedDk22-Apr-15 9:12
memberRedDk22-Apr-15 9:12 
QuestionSome Errors and functionality not working - Fixed for Developer Studio 2012 Pin
Member 103685446-Mar-15 20:41
memberMember 103685446-Mar-15 20:41 
AnswerRe: Some Errors and functionality not working - Fixed for Developer Studio 2012 Pin
YorkHwe8-Apr-15 23:17
memberYorkHwe8-Apr-15 23:17 
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
Member 1161661217-Apr-15 11:05
memberMember 1161661217-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
memberd200520-Feb-15 7:22 
QuestionOne question regarding Data store Pin
Tridip Bhattacharjee11-Feb-15 1:46
memberTridip 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
guillaume defretiere22-Oct-14 19:55
memberguillaume defretiere22-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
memberreplaysMike7-Mar-14 21:20 
QuestionCyrillic Pin
Shaitan-Babay4-Mar-14 23:24
memberShaitan-Babay4-Mar-14 23:24 
QuestionError Pin
lbdalmendray13-Feb-14 8:32
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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
somi663-Feb-14 2:52
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QuestionRe: Problem in Run Pin
nguyenquocbinh30-Sep-16 1:11
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QuestionReally great! Pin
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