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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

QuestionQuestion about use Pin
milestogofromhere8-Feb-11 11:05
Membermilestogofromhere8-Feb-11 11:05 
GeneralIndex out of range, Pin
PeaceTiger12-Jan-11 9:50
MemberPeaceTiger12-Jan-11 9:50 
GeneralRe: Index out of range, Pin
EricT.21-Jun-11 7:46
MemberEricT.21-Jun-11 7:46 
GeneralRGBLuminanceSource problem Pin
coecomos10-Jan-11 1:39
Membercoecomos10-Jan-11 1:39 
Generalgetcenter method throws error Pin
Rajkumar Ramakrishnan5-Jan-11 1:23
MemberRajkumar Ramakrishnan5-Jan-11 1:23 
GeneralISO/IEC 18004:2000 Pin
DCErick17-Dec-10 9:38
MemberDCErick17-Dec-10 9:38 
QuestionHow to integrate .NET Dll of QR Code with VB6 Pin
sathyamvasu17-Nov-10 21:18
Membersathyamvasu17-Nov-10 21:18 
AnswerRe: How to integrate .NET Dll of QR Code with VB6 Pin
xjorge15-Feb-11 14:18
Memberxjorge15-Feb-11 14:18 
GeneralDecode incorrectly when encode with unicode string Pin
Thanh Hoang3-Nov-10 23:22
professionalThanh Hoang3-Nov-10 23:22 
GeneralRe: Decode incorrectly when encode with unicode string Pin
Piotr Czekalski28-Nov-10 4:02
MemberPiotr Czekalski28-Nov-10 4:02 
GeneralRe: Decode incorrectly when encode with unicode string Pin
Manadar29-Dec-10 5:26
MemberManadar29-Dec-10 5:26 
GeneralRe: Decode incorrectly when encode with unicode string Pin
Piotr Czekalski3-Apr-11 8:01
MemberPiotr Czekalski3-Apr-11 8:01 
GeneralRe: Decode incorrectly when encode with unicode string Pin
Denys16-Aug-11 5:05
MemberDenys16-Aug-11 5:05 
GeneralIndexOutOfRangeException on Encode Pin
Sergio_7922-Oct-10 1:24
MemberSergio_7922-Oct-10 1:24 
GeneralIndexOutOfRangeException Pin
Superman100114-Oct-10 0:00
MemberSuperman100114-Oct-10 0:00 
GeneralRe: IndexOutOfRangeException Pin
Omar Del Toro M.14-Oct-10 12:07
MemberOmar Del Toro M.14-Oct-10 12:07 
AnswerRe: IndexOutOfRangeException Pin
pferril2-Nov-10 9:17
Memberpferril2-Nov-10 9:17 
GeneralRe: IndexOutOfRangeException Pin
dreamer_zl23-Nov-10 21:14
Memberdreamer_zl23-Nov-10 21:14 
GeneralRe: IndexOutOfRangeException Pin
Milos Miladinovic25-Nov-10 2:05
MemberMilos Miladinovic25-Nov-10 2:05 
AnswerRe: IndexOutOfRangeException Pin
Manadar29-Dec-10 5:06
MemberManadar29-Dec-10 5:06 
GeneralRe: IndexOutOfRangeException Pin
LaunaSere11-Mar-12 13:21
MemberLaunaSere11-Mar-12 13:21 
GeneralRe: IndexOutOfRangeException Pin
pakirikus8-Jul-12 22:34
Memberpakirikus8-Jul-12 22:34 
GeneralRe: IndexOutOfRangeException Pin
Member 998929215-Apr-13 7:14
MemberMember 998929215-Apr-13 7:14 
GeneralMy vote of 5 Pin
Leontti Ramos6-Oct-10 17:19
MemberLeontti Ramos6-Oct-10 17:19 
GeneralAnyone else having problems with lower case text encoding with this library Pin
Guy Swartwood4-Oct-10 9:18
MemberGuy Swartwood4-Oct-10 9:18 

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