Question

I am using Google Chart QR code , I have to send data more then 2k , I read document on

https://developers.google.com/chart/infographics/docs/qr_codes

its says that

The data to encode. Data can be digits (0-9), alphanumeric characters, binary bytes data,
or Kanji. You cannot mix data types within a QR code. The data must be UTF-8 
URL-encoded.Note that URLs have a 2K maximum length, so if you want to encode more than 
 2K bytes (minus the other URL characters), you will have to send your data using POST.

Can any one have sample that how can I send data using POST for Google QR – Code

Answer 1

I have used zxing library to solve my problem, I have downloaded Zxing Project and create DLL of it then reference that DLL into my project.

Encoding

        QRCodeWriter writer = new com.google.zxing.qrcode.QRCodeWriter();
        string str = string.Empty;
        for (int i = 0; i < 2000 ; i++)
            str += i;

        ByteMatrix byteMatrix = writer.encode(str, com.google.zxing.BarcodeFormat.QR_CODE, 300, 300);

        ImageConverter converter = new ImageConverter();
        // Sample of DexExpress Control 
        ASPxBinaryImage1.ContentBytes = (byte[])converter.ConvertTo(byteMatrix.ToBitmap(), typeof(byte[]));

        byte[] b = (byte[])converter.ConvertTo(byteMatrix.ToBitmap(), typeof(byte[]));
        string s = System.Convert.ToBase64String(b);
        //Sample of ASP.net Control
        image1.Attributes.Add("src", "data:image/png;base64," + s);

Decoding

        string strb64 = System.Convert.ToBase64String(b);

        QRCodeReader reader = new QRCodeReader();
        byte[] imageBytes = Convert.FromBase64String(strb64);
        MemoryStream ms = new MemoryStream(imageBytes, 0, imageBytes.Length);

        Bitmap bmp = new Bitmap(ms);

        LuminanceSource s = new RGBLuminanceSource(bmp, bmp.Width, bmp.Height);
        BinaryBitmap bb = new BinaryBitmap(new GlobalHistogramBinarizer(s));


        Result result = reader.decode(bb);

        //Store result into string
        string resultText = result.Text;