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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

GeneralVote of 3 Pin
Daniel_865-Aug-13 21:09
MemberDaniel_865-Aug-13 21:09 
QuestionThe famous indexoutofrange exception on line 654 Pin
dada20103-Jul-13 23:13
Memberdada20103-Jul-13 23:13 
Suggestioni hope , have help manual Pin
cheng11011018-Jun-13 1:22
Membercheng11011018-Jun-13 1:22 
Questionhow to create qr code automatically send sms Pin
Dư Bùi11-Jun-13 0:44
MemberDư Bùi11-Jun-13 0:44 
GeneralMy vote of 5 Pin
Member 97166372-Jun-13 23:57
MemberMember 97166372-Jun-13 23:57 
QuestionHow do i use it? Pin
Alexander Weis31-May-13 11:04
MemberAlexander Weis31-May-13 11:04 
GeneralMy vote of 5 Pin
nummer3131-May-13 9:47
Membernummer3131-May-13 9:47 
QuestionAbout QR COde Pin
Mohsin Azam25-May-13 20:44
MemberMohsin Azam25-May-13 20:44 
Questiongood Pin
linweneson15-May-13 0:20
Memberlinweneson15-May-13 0:20 
Questioncan't read result qrcode string Pin
Stutt10-May-13 5:00
MemberStutt10-May-13 5:00 
BugError correction Pin
Member 94134417-May-13 7:06
MemberMember 94134417-May-13 7:06 
QuestionGreat Job Pin
andrew_sa16-Apr-13 7:09
Memberandrew_sa16-Apr-13 7:09 
GeneralMy vote of 3 Pin
Gaurav.WhiteLotus8-Mar-13 0:13
MemberGaurav.WhiteLotus8-Mar-13 0:13 
GeneralRe: My vote of 3 Pin
Gaurav.WhiteLotus28-Jun-13 9:46
MemberGaurav.WhiteLotus28-Jun-13 9:46 
QuestionError Pin
bebo_s_802-Mar-13 23:47
Memberbebo_s_802-Mar-13 23:47 
GeneralMy vote of 5 Pin
peteSJ13-Feb-13 18:41
MemberpeteSJ13-Feb-13 18:41 
QuestionInput string length Pin
chrisawoods29-Jan-13 5:37
Memberchrisawoods29-Jan-13 5:37 
AnswerMessage Closed Pin
26-Mar-13 0:14
MemberNikeduban26-Mar-13 0:14 
QuestionHow to scan QR Code using Webcam in this library plz help PinPopular
Rohit Nagbhidkar24-Jan-13 2:30
MemberRohit Nagbhidkar24-Jan-13 2:30 
QuestionOther barcode types Pin
JBoada3-Jan-13 17:45
MemberJBoada3-Jan-13 17:45 
GeneralMy vote of 5 Pin
JBoada3-Jan-13 17:38
MemberJBoada3-Jan-13 17:38 
BugInvalid version in decode Pin
Member 954616112-Nov-12 12:13
MemberMember 954616112-Nov-12 12:13 
QuestionRDLC Report Pin
TintinLille11-Nov-12 1:32
MemberTintinLille11-Nov-12 1:32 
AnswerMessage Closed Pin
1-Apr-13 23:35
MemberNikeduban1-Apr-13 23:35 
QuestionHow to set CorrectionLevel and Version for Encoding? Pin
Member 94732758-Nov-12 23:34
MemberMember 94732758-Nov-12 23:34 

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