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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

GeneralRe: My vote of 3 Pin
Gaurav.WhiteLotus28-Jun-13 8:46
memberGaurav.WhiteLotus28-Jun-13 8:46 
QuestionError Pin
bebo_s_802-Mar-13 22:47
memberbebo_s_802-Mar-13 22:47 
GeneralMy vote of 5 Pin
peteSJ13-Feb-13 17:41
memberpeteSJ13-Feb-13 17:41 
QuestionInput string length Pin
chrisawoods29-Jan-13 4:37
memberchrisawoods29-Jan-13 4:37 
AnswerMessage Closed Pin
25-Mar-13 23:14
memberNikeduban25-Mar-13 23:14 
QuestionHow to scan QR Code using Webcam in this library plz help Pin
Rohit Nagbhidkar24-Jan-13 1:30
memberRohit Nagbhidkar24-Jan-13 1:30 
Questionqr code library Pin
Tarcode Michael15-Jan-13 15:25
memberTarcode Michael15-Jan-13 15:25 
QuestionOther barcode types Pin
JBoada3-Jan-13 16:45
memberJBoada3-Jan-13 16:45 
GeneralMy vote of 5 Pin
JBoada3-Jan-13 16:38
memberJBoada3-Jan-13 16:38 
BugInvalid version in decode Pin
Member 954616112-Nov-12 11:13
memberMember 954616112-Nov-12 11:13 
QuestionRDLC Report Pin
TintinLille11-Nov-12 0:32
memberTintinLille11-Nov-12 0:32 
AnswerMessage Closed Pin
1-Apr-13 22:35
memberNikeduban1-Apr-13 22:35 
QuestionHow to set CorrectionLevel and Version for Encoding? Pin
Member 94732758-Nov-12 22:34
memberMember 94732758-Nov-12 22:34 
QuestionHow to use this? Pin
Member 94732757-Nov-12 16:30
memberMember 94732757-Nov-12 16:30 
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) Pin
LuigiIT2-Nov-12 22:11
memberLuigiIT2-Nov-12 22:11 
GeneralMy vote of 5 Pin
Giovefi18-Oct-12 6:59
memberGiovefi18-Oct-12 6:59 
QuestionGreat job Pin
analog99917-Oct-12 6:53
memberanalog99917-Oct-12 6:53 
QuestionNot decoding QR code from scanned Image Pin
Jaydeep Jadav12-Oct-12 20:12
memberJaydeep Jadav12-Oct-12 20:12 
AnswerRe: Not decoding QR code from scanned Image Pin
Jaydeep Jadav18-Oct-12 19:20
memberJaydeep Jadav18-Oct-12 19:20 
QuestionUTF8 posing problem. Pin
Asnarpbio2-Oct-12 21:27
memberAsnarpbio2-Oct-12 21:27 
Questionwhere is QRVerToDataSize ? Pin
steve mettraux27-Sep-12 5:24
membersteve mettraux27-Sep-12 5:24 
QuestionProject Converted In VS 2010 Gives Build Error Pin
aqibsd22-Aug-12 23:46
memberaqibsd22-Aug-12 23:46 
AnswerRe: Project Converted In VS 2010 Gives Build Error Pin
cllamed14-Sep-12 6:37
membercllamed14-Sep-12 6:37 
QuestionError if Encode more than 124 characters Pin
Vivek Deshmukh13-Aug-12 2:16
memberVivek Deshmukh13-Aug-12 2:16 
AnswerRe: Error if Encode more than 124 characters Pin
mikeXmas21-Aug-12 19:35
membermikeXmas21-Aug-12 19:35 
AnswerRe: Error if Encode more than 124 characters Pin
saif.silver21-Dec-12 21:44
membersaif.silver21-Dec-12 21:44 
QuestionUsing the ThoughtWorks.QRCode.dll in a C++ application Pin
sonusudhanshu17-Jul-12 23:57
membersonusudhanshu17-Jul-12 23:57 
QuestionQR Code reader Pin
Code55810-Jul-12 23:37
memberCode55810-Jul-12 23:37 
QuestionNice Project - Really Helpful Pin
Member 57127826-Jul-12 23:18
memberMember 57127826-Jul-12 23:18 
QuestionCompile fails Pin
Nanosoft from Global20-Jun-12 18:42
memberNanosoft from Global20-Jun-12 18:42 
GeneralMy vote of 4 Pin
Burak Tunçbilek12-Jun-12 2:45
memberBurak Tunçbilek12-Jun-12 2:45 
QuestionFixed Files - New version at twitts homepage Pin
Member 86976874-Jun-12 8:21
memberMember 86976874-Jun-12 8:21 equivalent Pin
evilson28-Apr-12 9:48
memberevilson28-Apr-12 9:48 
QuestionIndex was outside the bounds of the array Pin
skanz27-Apr-12 4:47
memberskanz27-Apr-12 4:47 
AnswerRe: Index was outside the bounds of the array Pin
Member 117033111-May-12 17:11
memberMember 117033111-May-12 17:11 
GeneralRe: Index was outside the bounds of the array Pin
rapitoloco6-Aug-12 6:22
memberrapitoloco6-Aug-12 6:22 
GeneralRe: Index was outside the bounds of the array Pin
markoslo8-Oct-12 8:45
membermarkoslo8-Oct-12 8:45 
SuggestionFix BUG Pin
vadim30714-Apr-12 9:08
membervadim30714-Apr-12 9:08 
GeneralRe: Fix BUG Pin
Kiki Ariady Putra30-Apr-12 2:21
memberKiki Ariady Putra30-Apr-12 2:21 
GeneralRe: Fix BUG Pin
Qui Tran18-Jul-12 23:28
memberQui Tran18-Jul-12 23:28 
GeneralRe: Fix BUG Pin
Member 768863526-Jul-12 18:19
memberMember 768863526-Jul-12 18:19 
QuestionCode doesn't work (not compilable) Pin
vadim30714-Apr-12 1:49
membervadim30714-Apr-12 1:49 
QuestionCode with changes committed to google code Pin
hjgode15-Mar-12 0:33
memberhjgode15-Mar-12 0:33 
QuestionRe: Code with changes committed to google code Pin
sfitzge30812-Apr-12 3:26
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AnswerRe: Code with changes committed to google code Pin
hjgode12-Apr-12 7:22
memberhjgode12-Apr-12 7:22 
GeneralMy vote of 5 Pin
Nasenbaaer14-Mar-12 15:43
memberNasenbaaer14-Mar-12 15:43 
Questionqr code creation control for Pin
Zacbr12-Mar-12 5:39
memberZacbr12-Mar-12 5:39 
QuestionIndex was outside the bounds of the array Pin
LaunaSere11-Mar-12 7:49
memberLaunaSere11-Mar-12 7:49 
AnswerRe: Index was outside the bounds of the array Pin
hjgode12-Mar-12 23:57
memberhjgode12-Mar-12 23:57 
GeneralRe: Index was outside the bounds of the array Pin
LaunaSere16-Mar-12 5:49
memberLaunaSere16-Mar-12 5:49 

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