Click here to Skip to main content
12,630,420 members (30,675 online)
Click here to Skip to main content
Add your own
alternative version


397 bookmarked

Open Source QRCode Library

, 20 Sep 2007 CPOL
Rate this:
Please Sign up or sign in to vote.
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.

You may also be interested in...


Comments and Discussions

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 Automatically Removed 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 
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 Pin
Tarcode Michael15-Jan-13 16:25
memberTarcode Michael15-Jan-13 16:25 
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 Automatically Removed Pin
1-Apr-13 23:35
memberNikeduban1-Apr-13 23:35 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Terms of Use | Mobile
Web02 | 2.8.161205.3 | Last Updated 20 Sep 2007
Article Copyright 2007 by twit88
Everything else Copyright © CodeProject, 1999-2016
Layout: fixed | fluid