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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

GeneralIt can't work with Chinese font!! Pin
hrmai8-Aug-09 3:52
Memberhrmai8-Aug-09 3:52 
AnswerRe: It can't work with Chinese font!! Pin
JackyFan23-Sep-09 14:49
MemberJackyFan23-Sep-09 14:49 
QuestionRe: It can't work with Chinese font!! Pin
sunshinerao6-Oct-09 4:58
Membersunshinerao6-Oct-09 4:58 
QuestionRe: It can't work with Chinese font!! Pin
allenallen27-Apr-10 20:33
Memberallenallen27-Apr-10 20:33 
GeneralWeb Usage Guidance Pin
jon.waller11-Jun-09 10:37
Memberjon.waller11-Jun-09 10:37 
GeneralProblem building program Pin
anwaar130-May-09 12:37
Memberanwaar130-May-09 12:37 
GeneralRe: Problem building program Pin
tammeniit31-Jul-09 0:14
Membertammeniit31-Jul-09 0:14 
GeneralThank You Pin
amgadhs15-May-09 11:08
Memberamgadhs15-May-09 11:08 
Thank you for this valuable code.Thumbs Up | :thumbsup:

Amgad Suliman
My Blog: CodeHill

Generalwtf Pin
Jasmine Pomelo9-May-09 13:54
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GeneralIndexOutOfRangeException in rsTemp [modified] Pin
aprilkacau10-Apr-09 2:29
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RantRe: IndexOutOfRangeException in rsTemp Pin
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GeneralRe: IndexOutOfRangeException in rsTemp Pin
jonataspc30-Jul-09 7:17
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AnswerRe: IndexOutOfRangeException in rsTemp [modified] Pin
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QuestionIs this free? Pin
Carl00722-Mar-09 20:16
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AnswerRe: Is this free? Pin
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GeneralRe: Is this free? Pin
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GeneralError on VisualStudio 2008 Pin
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GeneralRe: Error on VisualStudio 2008 Pin
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GeneralResources.GetResource Pin
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GeneralRe: Resources.GetResource Pin
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