C# 生成和识别二维码

本来认为这功能在网上一搜一大堆，结果确实如此。但没有一个能用的，给一个微信一码通二维码，全都识别不了。

要么就是要收费，收个毛线，这东西都要收费，以后程序员写个软件岂不还没写就亏本了。

于是乎一顿搜索，经测试代码稳定，无论是纯二维码还是复杂图像嵌入二维码，均可识别。

第一步：Install-Package ZXing.Net -Version 0.16.6 

引入这个com组件

第二步，写代码：

class Program
    {
        static void Main(string[] args)
        {
            var data = "http://programmingnotes.org/";

            // Encode data to a QR code byte array
            var bytes = CreateQRCode(data);

            //File.WriteAllBytes(@"c:\a.png", bytes);

            Console.WriteLine($"Length: {bytes.Length}");

            // Decode QR code to a string
            var result = ReadQRCode(bytes);

            var result2 = ReadQRCode(File.ReadAllBytes(@"E:\Desktop\erweima\微信图片_20210721150957.jpg"));

            Console.WriteLine($"Result: {result}");
        }

        /// <summary>
        /// Converts a string and encodes it to a QR code byte array
        /// </summary>
        /// <param name="data">The data to encode</param>
        /// <param name="height">The height of the QR code</param>
        /// <param name="width">The width of the QR code</param>
        /// <param name="margin">The margin around the QR code</param>
        /// <returns>The byte array of the data encoded into a QR code</returns>
        public static byte[] CreateQRCode(string data, int height = 100
                        , int width = 100, int margin = 0)
        {
            byte[] bytes = null;
            var barcodeWriter = new ZXing.BarcodeWriter()
            {
                Format = ZXing.BarcodeFormat.QR_CODE,
                Options = new ZXing.QrCode.QrCodeEncodingOptions()
                {
                    Height = height,
                    Width = width,
                    Margin = margin
                }
            };
            using (var image = barcodeWriter.Write(data))
            {
                using (var stream = new System.IO.MemoryStream())
                {
                    image.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
                    bytes = stream.ToArray();
                }
            }
            return bytes;
        }

        /// <summary>
        /// Converts a QR code and decodes it to its string data 
        /// </summary>
        /// <param name="bytes">The QR code byte array</param> 
        /// <returns>The string data decoded from the QR code</returns>
        public static string ReadQRCode(byte[] bytes)
        {
            var result = string.Empty;
            using (var stream = new System.IO.MemoryStream(bytes))
            {
                using (var image = System.Drawing.Image.FromStream(stream))
                {
                    var barcodeReader = new ZXing.BarcodeReader();
                    var decoded = barcodeReader.Decode((System.Drawing.Bitmap)image);
                    if (decoded != null)
                    {
                        result = decoded.Text;
                    }
                }
            }
            return result;
        }
    }