QRCode

public sealed class QRCodeGeneratorService : IQRCodeGeneratorService
{
    // QR code generator
    private readonly QRCodeGenerator _qrCodeGenerator;

    // Constructor
    public QRCodeGeneratorService()
    {
        _qrCodeGenerator = new QRCodeGenerator();
    }

    // Generate a QR code from a text string
    public string GenerateQRCodeFromText(string text)
    {
        try
        {
            if (string.IsNullOrEmpty(text))
                throw new ArgumentNullException(nameof(text), "Text cannot be null or empty.");

            // Create QR code data
            var data = _qrCodeGenerator.CreateQrCode(text, QRCodeGenerator.ECCLevel.Q);

            // Create bitmap from QR code data
            var bitmap = new BitmapByteQRCode(data);
            var qrCodeBytes = bitmap.GetGraphic(20);

            // Convert bitmap to image
            using var ms = new MemoryStream(qrCodeBytes);
            var qrCodeImage = new Bitmap(ms);

            // Convert image to base64 string
            using var msBase64 = new MemoryStream();
            qrCodeImage.Save(msBase64, ImageFormat.Png);
            var base64String = Convert.ToBase64String(msBase64.ToArray());

            return base64String;
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            throw;
        }
    }
}