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Posted 20 Sep 2007


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Open Source QRCode Library

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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

GeneralExcellent Project Pin
korrawit10-Feb-08 10:13
Memberkorrawit10-Feb-08 10:13 
QuestionWhy Not All QRCode Decoded? Pin
pbsclubs14-Jan-08 16:26
Memberpbsclubs14-Jan-08 16:26 
AnswerRe: Why Not All QRCode Decoded? Pin
pou62919-Jan-08 16:26
Memberpou62919-Jan-08 16:26 
Questionwhen opening the project in visual studio Pin
mkavita8-Nov-07 6:08
Membermkavita8-Nov-07 6:08 
AnswerRe: when opening the project in visual studio Pin
BruceN9-Nov-07 19:22
MemberBruceN9-Nov-07 19:22 
GeneralRe: when opening the project in visual studio Pin
mkavita19-Nov-07 5:41
Membermkavita19-Nov-07 5:41 
Questionproblem? Pin
pkershin24-Sep-07 6:51
Memberpkershin24-Sep-07 6:51 
AnswerRe: problem? PinPopular
mengwangk24-Sep-07 20:31
Membermengwangk24-Sep-07 20:31 
Refer to the posted forum in the website. You should be able to get it working following the instructions.


GeneralRe: problem? Pin
Giga55478-Jan-08 2:14
MemberGiga55478-Jan-08 2:14 
GeneralRe: problem? Pin
smalolepszy29-Apr-08 2:30
Membersmalolepszy29-Apr-08 2:30 
GeneralRe: problem? Pin
deadshot1233-May-08 19:08
Memberdeadshot1233-May-08 19:08 
GeneralRe: problem? Pin
deadshot1233-May-08 21:27
Memberdeadshot1233-May-08 21:27 
GeneralRe: problem? Pin
chrismok29-May-08 2:33
Memberchrismok29-May-08 2:33 
GeneralRe: problem? Pin
fmfmffllflflff30-May-08 14:19
Memberfmfmffllflflff30-May-08 14:19 
GeneralRe: problem? Pin
fmfmffllflflff30-May-08 14:16
Memberfmfmffllflflff30-May-08 14:16 
GeneralAwesome Pin
merlin98120-Sep-07 5:47
professionalmerlin98120-Sep-07 5:47 

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