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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

GeneralMy vote of 5 Pinmembernummer3131-May-13 8:47 
QuestionAbout QR COde PinmemberMohsin Azam25-May-13 19:44 
Questiongood Pinmemberlinweneson14-May-13 23:20 
Questioncan't read result qrcode string PinmemberStutt10-May-13 4:00 
BugError correction PinmemberMember 94134417-May-13 6:06 
QuestionGreat Job Pinmemberandrew_sa16-Apr-13 6:09 
GeneralMy vote of 3 PinmemberGaurav.WhiteLotus7-Mar-13 23:13 
GeneralMessage Automatically Removed Pinmembersdafsafss224-Apr-13 16:17 
GeneralRe: My vote of 3 PinmemberGaurav.WhiteLotus28-Jun-13 8:46 
QuestionError Pinmemberbebo_s_802-Mar-13 22:47 
GeneralMy vote of 5 PinmemberpeteSJ13-Feb-13 17:41 
QuestionInput string length Pinmemberchrisawoods29-Jan-13 4:37 
AnswerMessage Automatically Removed PinmemberNikeduban25-Mar-13 23:14 
QuestionHow to scan QR Code using Webcam in this library plz help PinmemberRohit Nagbhidkar24-Jan-13 1:30 
hi guys i am making a program to scan qr code from webcam in real time and if the program scans qr code then it will save it to database
i have tried with emgu cv stuff bt it gave exceptions when not found in each frame making program unstable
is there is any way for that??
here is my code...
runnable bt very slow..Frown | :(
Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Text
Imports System.Windows.Forms
Imports System.Drawing.Imaging
Imports ThoughtWorks.QRCode.Codec
Imports ThoughtWorks.QRCode.Codec.Data
Imports ThoughtWorks.QRCode.Codec.Util
Imports Emgu.CV
Imports Emgu.CV.Structure
Imports Emgu.Util
Public Class Form1
Dim picDecode As Image
Dim Capturez0 As Capture = New Capture(0)
Dim imagez0 As Image(Of Bgr, Byte)

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
imagez0 = Capturez0.RetrieveBgrFrame
Dim att As New numTryDecode.QRCodeDecoder
PictureBox1.Image = imagez0.ToBitmap()
Dim decoder As New QRCodeDecoder()
'QRCodeDecoder.Canvas = New ConsoleCanvas()
Dim decodedString As [String] = decoder.decode(New QRCodeBitmapImage(New Bitmap(imagez0.ToBitmap())))
txtDecodedData.Text = decodedString
Catch ex As Exception
End Try
End Sub

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
End Class
plz help
Questionqr code library PinmemberTarcode Michael15-Jan-13 15:25 
QuestionOther barcode types PinmemberJBoada3-Jan-13 16:45 
GeneralMy vote of 5 PinmemberJBoada3-Jan-13 16:38 
BugInvalid version in decode PinmemberMember 954616112-Nov-12 11:13 
QuestionRDLC Report PinmemberTintinLille11-Nov-12 0:32 
AnswerMessage Automatically Removed PinmemberNikeduban1-Apr-13 22:35 
QuestionHow to set CorrectionLevel and Version for Encoding? PinmemberMember 94732758-Nov-12 22:34 
QuestionHow to use this? PinmemberMember 94732757-Nov-12 16:30 
QuestionVersion for Visual Basic 6 (VB6) PinmemberLuigiIT2-Nov-12 22:11 
GeneralMy vote of 5 PinmemberGiovefi18-Oct-12 6:59 
QuestionGreat job Pinmemberanalog99917-Oct-12 6:53 
QuestionNot decoding QR code from scanned Image PinmemberJaydeep Jadav12-Oct-12 20:12 
AnswerRe: Not decoding QR code from scanned Image PinmemberJaydeep Jadav18-Oct-12 19:20 
QuestionUTF8 posing problem. PinmemberAsnarpbio2-Oct-12 21:27 
Questionwhere is QRVerToDataSize ? Pinmembersteve mettraux27-Sep-12 5:24 
QuestionProject Converted In VS 2010 Gives Build Error Pinmemberaqibsd22-Aug-12 23:46 
AnswerRe: Project Converted In VS 2010 Gives Build Error Pinmembercllamed14-Sep-12 6:37 
QuestionError if Encode more than 124 characters PinmemberVivek Deshmukh13-Aug-12 2:16 
AnswerRe: Error if Encode more than 124 characters PinmembermikeXmas21-Aug-12 19:35 
AnswerRe: Error if Encode more than 124 characters Pinmembersaif.silver21-Dec-12 21:44 
QuestionUsing the ThoughtWorks.QRCode.dll in a C++ application Pinmembersonusudhanshu17-Jul-12 23:57 
QuestionQR Code reader PinmemberCode55810-Jul-12 23:37 
QuestionNice Project - Really Helpful PinmemberMember 57127826-Jul-12 23:18 
QuestionCompile fails PinmemberNanosoft from Global20-Jun-12 18:42 
GeneralMy vote of 4 PinmemberBurak Tunçbilek12-Jun-12 2:45 
QuestionFixed Files - New version at twitts homepage PinmemberMember 86976874-Jun-12 8:21 equivalent Pinmemberevilson28-Apr-12 9:48 
QuestionIndex was outside the bounds of the array Pinmemberskanz27-Apr-12 4:47 
AnswerRe: Index was outside the bounds of the array PinmemberMember 117033111-May-12 17:11 
GeneralRe: Index was outside the bounds of the array Pinmemberrapitoloco6-Aug-12 6:22 
GeneralRe: Index was outside the bounds of the array Pinmembermarkoslo8-Oct-12 8:45 
SuggestionFix BUG Pinmembervadim30714-Apr-12 9:08 
GeneralRe: Fix BUG PinmemberKiki Ariady Putra30-Apr-12 2:21 
GeneralRe: Fix BUG PinmemberQui Tran18-Jul-12 23:28 
GeneralRe: Fix BUG PinmemberMember 768863526-Jul-12 18:19 
QuestionCode doesn't work (not compilable) Pinmembervadim30714-Apr-12 1:49 

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