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Open Source QRCode Library

, 20 Sep 2007 CPOL
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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

Web Developer
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: My vote of 3 Pin
Gaurav.WhiteLotus at 28-Jun-13 9:46
memberGaurav.WhiteLotus28-Jun-13 9:46 
QuestionError Pin
bebo_s_80 at 2-Mar-13 23:47
memberbebo_s_802-Mar-13 23:47 
GeneralMy vote of 5 Pin
peteSJ at 13-Feb-13 18:41
memberpeteSJ13-Feb-13 18:41 
QuestionInput string length Pin
chrisawoods at 29-Jan-13 5:37
memberchrisawoods29-Jan-13 5:37 
AnswerMessage Automatically Removed Pin
at 26-Mar-13 0:14
memberNikeduban26-Mar-13 0:14 
QuestionHow to scan QR Code using Webcam in this library plz help Pin
Rohit Nagbhidkar at 24-Jan-13 2:30
memberRohit Nagbhidkar24-Jan-13 2:30 
Questionqr code library Pin
Tarcode Michael at 15-Jan-13 16:25
memberTarcode Michael15-Jan-13 16:25 
QuestionOther barcode types Pin
JBoada at 3-Jan-13 17:45
memberJBoada3-Jan-13 17:45 

Excellent article. I would like to know if you have a project that covers other barcode types like code 128?

Best Regards,

Juan Boada
GeneralMy vote of 5 Pin
JBoada at 3-Jan-13 17:38
memberJBoada3-Jan-13 17:38 
BugInvalid version in decode Pin
Member 9546161 at 12-Nov-12 12:13
memberMember 954616112-Nov-12 12:13 
QuestionRDLC Report Pin
TintinLille at 11-Nov-12 1:32
memberTintinLille11-Nov-12 1:32 
AnswerMessage Automatically Removed Pin
at 1-Apr-13 23:35
memberNikeduban1-Apr-13 23:35 
QuestionHow to set CorrectionLevel and Version for Encoding? Pin
Member 9473275 at 8-Nov-12 23:34
memberMember 94732758-Nov-12 23:34 
QuestionHow to use this? Pin
Member 9473275 at 7-Nov-12 17:30
memberMember 94732757-Nov-12 17:30 
QuestionVersion for Visual Basic 6 (VB6) Pin
LuigiIT at 2-Nov-12 23:11
memberLuigiIT2-Nov-12 23:11 
GeneralMy vote of 5 Pin
Giovefi at 18-Oct-12 7:59
memberGiovefi18-Oct-12 7:59 
QuestionGreat job Pin
analog999 at 17-Oct-12 7:53
memberanalog99917-Oct-12 7:53 
QuestionNot decoding QR code from scanned Image Pin
Jaydeep Jadav at 12-Oct-12 21:12
memberJaydeep Jadav12-Oct-12 21:12 
AnswerRe: Not decoding QR code from scanned Image Pin
Jaydeep Jadav at 18-Oct-12 20:20
memberJaydeep Jadav18-Oct-12 20:20 
QuestionUTF8 posing problem. Pin
Asnarpbio at 2-Oct-12 22:27
memberAsnarpbio2-Oct-12 22:27 
Questionwhere is QRVerToDataSize ? Pin
steve mettraux at 27-Sep-12 6:24
membersteve mettraux27-Sep-12 6:24 
QuestionProject Converted In VS 2010 Gives Build Error Pin
aqibsd at 23-Aug-12 0:46
memberaqibsd23-Aug-12 0:46 
AnswerRe: Project Converted In VS 2010 Gives Build Error Pin
cllamed at 14-Sep-12 7:37
membercllamed14-Sep-12 7:37 
QuestionError if Encode more than 124 characters Pin
Vivek Deshmukh at 13-Aug-12 3:16
memberVivek Deshmukh13-Aug-12 3:16 
AnswerRe: Error if Encode more than 124 characters Pin
mikeXmas at 21-Aug-12 20:35
membermikeXmas21-Aug-12 20:35 

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