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Open Source QRCode Library

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4.92/5 (147 votes)
20 Sep 2007CPOL1 min read 6M   192.3K   421   334
How to use QRCode library to encode and decode QRCode
Screenshot - qrcode_app_decode.jpg

Introduction

In this article, I will briefly describe the functionalities of the QRCode library.

Background

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

C#
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!");
              return;
          }
          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;

History

  • 20th September, 2007: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
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.

https://mengwangk.github.io/

Comments and Discussions

 
GeneralSOS Pin
peterlengos16-May-11 22:52
peterlengos16-May-11 22:52 
GeneralRe: SOS Pin
Anders Lybecker19-May-11 3:17
Anders Lybecker19-May-11 3:17 
GeneralHow to use the qrcode library Pin
Jelena Hazlehurst13-May-11 18:07
Jelena Hazlehurst13-May-11 18:07 
QuestionIncrease max number of characters to encode Pin
kagearm28-Apr-11 1:42
kagearm28-Apr-11 1:42 
AnswerRe: Increase max number of characters to encode Pin
jeanso14-May-11 17:59
jeanso14-May-11 17:59 
Generaljust wanna say thank you Pin
Humsyong27-Apr-11 16:26
Humsyong27-Apr-11 16:26 
GeneralHow to increase maxDataCodewords? Pin
kagearm20-Apr-11 4:42
kagearm20-Apr-11 4:42 
QuestionNoob trying to get this to work in MS Access Pin
jaqqaj18-Apr-11 12:55
jaqqaj18-Apr-11 12:55 
First of all, thanks for the GREAT library. After installation, the demo project works great.

I followed these instructions and and registered the .dll and created a type library, then added the library to my references in MS Access (not shown on that link).

http://www.geeksengine.com/article/register-dll.html[^]

Then I put this code behind a button on a form:
Private Sub btnEncode_Click()
 Dim objqrCode As QRCodeEncoder
 Set objqrCode = New QRCodeEncoder
 Dim strData As String
 Dim imgImage As Image

 objqrCode.QRCodeEncodeMode = 2
 objqrCode.QRCodeScale = 3
 objqrCode.QRCodeVersion = 10
 objqrCode.QRCodeErrorCorrect = 0
 strData = Me.txtData
 'imgImage.Picture = objqrCode.Encode(strData)
 'Me.Image2.Picture = imgImage.Picture
 Me.Image2.Picture = objqrCode.Encode(strData)


End Sub


The form just has three controls, Image2, txtData, and the button. I just hard coded the other settings to see if I could get this to work.

When I click the button I get "Runtime Error '5': Invalid procedure call or argument" debug takes me to the last line. You can see I tried some other stuff in there.

Is this not working because I need to recompile the assembly to make it COM visible?

Any help would be greatly appreciated! Thanks for looking.
QuestionDLL size Pin
James Knopp17-Apr-11 22:28
James Knopp17-Apr-11 22:28 
GeneralMy vote of 5 Pin
washingto21-Mar-11 21:18
washingto21-Mar-11 21:18 
QuestionHow to encode byte data? Pin
jjdd8821-Mar-11 13:05
jjdd8821-Mar-11 13:05 
GeneralMy vote of 5 Pin
Pavel Vladov16-Mar-11 6:00
Pavel Vladov16-Mar-11 6:00 
Generalthanks mate Pin
Member 73616421-Mar-11 9:42
Member 73616421-Mar-11 9:42 
GeneralAPP Web Pin
ruben_zer09-Feb-11 6:40
ruben_zer09-Feb-11 6:40 
GeneralRe: APP Web Pin
Member 769305021-Feb-11 13:02
Member 769305021-Feb-11 13:02 
GeneralRe: APP Web Pin
Iunstir27-Feb-11 21:46
Iunstir27-Feb-11 21:46 
AnswerRe: APP Web Pin
oware27-Oct-11 7:23
oware27-Oct-11 7:23 
GeneralRe: APP Web Pin
NinjaCat88!13-Feb-12 5:59
NinjaCat88!13-Feb-12 5:59 
GeneralRe: APP Web Pin
oware13-Feb-12 7:42
oware13-Feb-12 7:42 
GeneralRe: APP Web Pin
NinjaCat88!13-Feb-12 8:09
NinjaCat88!13-Feb-12 8:09 
GeneralRe: APP Web Pin
oware13-Feb-12 9:35
oware13-Feb-12 9:35 
QuestionQuestion about use Pin
milestogofromhere8-Feb-11 10:05
milestogofromhere8-Feb-11 10:05 
GeneralIndex out of range, Pin
PeaceTiger12-Jan-11 8:50
PeaceTiger12-Jan-11 8:50 
GeneralRe: Index out of range, Pin
EricT.21-Jun-11 6:46
EricT.21-Jun-11 6:46 
GeneralRGBLuminanceSource problem Pin
coecomos10-Jan-11 0:39
coecomos10-Jan-11 0:39 

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