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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

GeneralRe: Anyone else having problems with lower case text encoding with this library Pin
Superman10016-Oct-10 0:56
MemberSuperman10016-Oct-10 0:56 
GeneralRe: Anyone else having problems with lower case text encoding with this library Pin
Guy Swartwood6-Oct-10 5:03
MemberGuy Swartwood6-Oct-10 5:03 
Question当version为30以上时,解码报错? Pin
jason_fang25-Sep-10 21:02
Memberjason_fang25-Sep-10 21:02 
GeneralMy vote of 5 Pin
exergonic20-Sep-10 16:32
Memberexergonic20-Sep-10 16:32 
GeneralMy vote of 4 Pin
Nathan Swann12-Sep-10 6:15
MemberNathan Swann12-Sep-10 6:15 
QuestionIf I want to add an other textbox, How should I do ?? Pin
harkkwon5-Sep-10 21:59
Memberharkkwon5-Sep-10 21:59 
QuestionQR Code library called by a VB6 application Pin
mbarbaglia26-Aug-10 12:58
Membermbarbaglia26-Aug-10 12:58 
GeneralMy vote of 5 Pin
asingc20-Jul-10 15:20
Memberasingc20-Jul-10 15:20 
GeneralHookup to webcam Pin
zeek7-Jul-10 3:37
Memberzeek7-Jul-10 3:37 
AnswerRe: Hookup to webcam Pin
eijun15-Jul-10 8:39
Membereijun15-Jul-10 8:39 
GeneralRe: Hookup to webcam Pin
vrushikesh16-Jul-10 5:07
Membervrushikesh16-Jul-10 5:07 
GeneralRe: Hookup to webcam Pin
Jesmie Nguyen4-Nov-10 22:26
MemberJesmie Nguyen4-Nov-10 22:26 
GeneralMy vote of 5 Pin
bluescorpio11076-Jul-10 18:17
Memberbluescorpio11076-Jul-10 18:17 
NewsAwesome! Pin
ben@kbvcorp.com1-Jul-10 9:29
Memberben@kbvcorp.com1-Jul-10 9:29 
GeneralThis is exact what i need, thanks Pin
Xiaosheng Wang30-Jun-10 6:14
MemberXiaosheng Wang30-Jun-10 6:14 
GeneralExcellent !!! Pin
Al Rice23-Jun-10 16:31
MemberAl Rice23-Jun-10 16:31 
QuestionRS decoder not working? Pin
davb30046-Jun-10 2:31
Memberdavb30046-Jun-10 2:31 
AnswerRe: RS decoder not working? Pin
Scootty9-Jun-10 23:32
MemberScootty9-Jun-10 23:32 
GeneralRe: RS decoder not working? Pin
WashCaps5-Aug-10 8:23
MemberWashCaps5-Aug-10 8:23 
General!!!!!!!!HELP!!!!!!!!!!!!!!! Pin
ssnv.girish20-May-10 0:19
Memberssnv.girish20-May-10 0:19 
GeneralHelp About Resource Files Pin
ssnv.girish20-May-10 0:17
Memberssnv.girish20-May-10 0:17 
GeneralYES! Thank you!(!) Simple windows program to read / decode QR code - Zoinks! Pin
unRheal23-Apr-10 15:35
MemberunRheal23-Apr-10 15:35 
GeneralJust want to say thank you Pin
Member 39749963-Apr-10 13:59
MemberMember 39749963-Apr-10 13:59 
GeneralEcode/decode VCard Info Pin
rohit_bciit31-Jan-10 4:44
Memberrohit_bciit31-Jan-10 4:44 
AnswerRe: Ecode/decode VCard Info [modified] Pin
Nismoto10-Mar-10 16:52
MemberNismoto10-Mar-10 16:52 

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