how to create a qrcode?

Question

how to create qrCode with url into a stream in api?

Answer 1

Hi @mc,

This may be what you want.

First, install QRCode Nuget Package:

Controller and Extension:

[Route("api/[controller]")]
[ApiController]
public class QrcodeController : ControllerBase
{
    [HttpPost]
    public string CreateQRCode(string qRCode)
    {
        QRCodeGenerator QrGenerator = new QRCodeGenerator();
        QRCodeData QrCodeInfo = QrGenerator.CreateQrCode(qRCode, QRCodeGenerator.ECCLevel.Q);
        QRCode QrCode = new QRCode(QrCodeInfo);

        //save qrr file to wwwroot/qrr folder
        //string fileGuid = Guid.NewGuid().ToString().Substring(0, 4);
        //QrCodeInfo.SaveRawData("wwwroot/qrr/file-" + fileGuid + ".qrr", QRCodeData.Compression.Uncompressed);
        Bitmap QrBitmap = QrCode.GetGraphic(60);
        byte[] BitmapArray = QrBitmap.BitmapToByteArray();
        string QrUri = string.Format("data:image/png;base64,{0}", Convert.ToBase64String(BitmapArray));
        //ViewBag.QrCodeUri = QrUri;
        return QrUri;
    }
}

public static class BitmapExtension
{
    public static byte[] BitmapToByteArray(this Bitmap bitmap)
    {
        using (MemoryStream ms = new MemoryStream())
        {
            bitmap.Save(ms, ImageFormat.Png);
            return ms.ToArray();
        }
    }
}

If you want to load the QR code after calling this api, the string QrUri output by this api is the src of the img tag.

For more details, you can check this GitHub Respositiory.

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Best Regards,

Chen Li