I’ve been using the .NET MessagingToolkit.QRCode library for some time on my websites in order to generate QR codes with custom images on top and until now I have had no problems at all with this library.
Recently, the data I need to encode has gotten larger as a result of system growth and attempting to encode this data within a QR code has been causing internal “index out of range” exceptions within the Encode method of the QRCodeEncoder class.
Through testing I have noted that the maximum number of characters this method appears to accept is 86 and anything greater than this will throw the exception. Changing the encoding type of the string passed in does not help.
I did note that the version of the library I was using was out of date, however, updating to the latest version also did not solve the problem.
Has anyone else experienced this issue with the library and found a solution? Alternatively, is there another library I could use which does not have such problems?
The exception details are below:
2012-10-01 17:39:52,098 Error: System.IndexOutOfRangeException: Index was outside the bounds of the array.
at MessagingToolkit.QRCode.Codec.QRCodeEncoder.divideDataBy8Bits(Int32[] data, SByte[] bits, Int32 maxDataCodewords)
at MessagingToolkit.QRCode.Codec.QRCodeEncoder.calQrcode(Byte[] qrcodeData)
at MessagingToolkit.QRCode.Codec.QRCodeEncoder.Encode(String content, Encoding encoding)
at MessagingToolkit.QRCode.Codec.QRCodeEncoder.Encode(String content)
On the official page for that library there is a short description of solution for your problem: http://platform.twit88.com/news/60. I don’t know if that would fix your problem though. I would find the source code of the library and debug through it to see the reason for the error.
hm… can’t find the source code anywhere. So get in touch with the authors and ask them.
If that does not work out, I would change the library to something else. I have used QrCode.Net with MVC successfully and have some sample code how to integrate it to MVC, if you like.