需在nuget 添加此dll

///content字符串

public static string GetQRCode(string content, int moduleSize = 9)

{

   var encoder = new QrEncoder(ErrorCorrectionLevel.M);

   QrCode qrCode = encoder.Encode(content);

   GraphicsRenderer render = new GraphicsRenderer(new FixedModuleSize(moduleSize, QuietZoneModules.Two), Brushes.Black, Brushes.White);

   MemoryStream memoryStream = new MemoryStream();

   render.WriteToStream(qrCode.Matrix, ImageFormat.Jpeg, memoryStream);

   byte[] arr = memoryStream.ToArray();

   string base64Str = "data:image/jpeg;base64," + Convert.ToBase64String(arr);

   return base64Str;

}