C#生成二维码，返回Base64字符

　　using ThoughtWorks.QRCode.Codec;
　　public static string GetQrCodeImage()
        {
            //二维码生成对象，需引用DLL
            QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();

            qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;

            qrCodeEncoder.QRCodeVersion = 0;//版本控制，根据dll的版本，不同版本支持的二维码内容存储的长度不同

            qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;

            string data = string.Format(ConfigurationManager.AppSettings["mpServicePath"], "Html/ProviderReg/ProviderOpen.aspx?QrCodeInfoId=001");
            qrCodeEncoder.QRCodeScale = data.Length;

            //data为扫描二维码跳转的地址（也可以是文本）
            System.Drawing.Bitmap image = qrCodeEncoder.Encode(data, Encoding.UTF8);

            System.IO.MemoryStream MStream = new System.IO.MemoryStream();
            image.Save(MStream, System.Drawing.Imaging.ImageFormat.Png);

            byte[] by = new byte[MStream.Length];
            MStream.Position = 0;
            MStream.Read(by, 0, (int)MStream.Length);//写入进去。
            MStream.Close();//释放资源

            string base64 = Convert.ToBase64String(by);//转换成字节流
            Dictionarystring, string> dic = new Dictionarystring, string>();
            dic["base64"] = base64;
            JavaScriptSerializer jss = new JavaScriptSerializer();
            return jss.Serialize(dic);//返回json格式
        }