public ActionResult MakeQRCodeImage(string url)
{
string str = StringService.FromHexString(url);
//初始化二维码生成工具
QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;
qrCodeEncoder.QRCodeVersion = 0;
qrCodeEncoder.QRCodeScale = 4;
//将字符串生成二维码图片
Bitmap image = qrCodeEncoder.Encode(str, Encoding.Default);
//保存为PNG到内存流
MemoryStream ms = new MemoryStream();
image.Save(ms, ImageFormat.Png);
//输出二维码图片
byte[] bytes = ms.GetBuffer();
return(File(bytes, @"image/jpeg"));
}