1.添加包

先使用NuGet包管理器添加ThoughtWorks.QRCoder

2.写代码

引入包

using ThoughtWorks.QRCode.Codec;
using ThoughtWorks.QRCode.Codec.Data;

二维码工具类

static class QRCoderTools
    {
        static Bitmap AddWhiteBorder(Bitmap bitmap, int borderSize)
        {
            Bitmap bmp = new Bitmap(bitmap.Width + borderSize * 2, bitmap.Height + borderSize * 2, bitmap.PixelFormat);
            Graphics bg = Graphics.FromImage(bmp);
            bg.Clear(Color.White);
            bg.DrawImage(bitmap, borderSize, borderSize);

            return bmp;
        }

        /// <summary>
        /// 生成二维码
        /// </summary>
        /// <param name="msg">信息</param>
        /// <param name="version">版本 1 ~ 40</param>
        /// <param name="pixel">像素点大小</param>
        /// <param name="borderSize">白边大小</param>
        /// <returns>位图</returns>
        public static Bitmap Encode(string msg, int version, int pixel, int borderSize)
        {
            QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
            qrCodeEncoder.QRCodeVersion = version;
            qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
            qrCodeEncoder.QRCodeScale = pixel;

            Bitmap bmp = null;
            try
            {
                bmp = qrCodeEncoder.Encode(msg, Encoding.UTF8);
            }
            catch (System.IndexOutOfRangeException)
            {
                MessageBox.Show("数据量过大,请调大Version值");
                return null;
            }
            
            Bitmap qr_code_image = AddWhiteBorder(bmp, borderSize);
            bmp.Dispose();
            return qr_code_image;
        }

        /// <summary>
        /// 识别二维码
        /// </summary>
        /// <param name="bmp">包含二维码的图片</param>
        /// <returns>二维码内容</returns>
        public static string Decode(Bitmap bmp)
        {
            QRCodeDecoder qrCodeDecoder = new QRCodeDecoder();
            QRCodeBitmapImage qrCodeBitmapImage = new QRCodeBitmapImage(bmp);
            string ret = string.Empty;
            try
            {
                ret = qrCodeDecoder.decode(qrCodeBitmapImage, Encoding.UTF8);
            }
            catch (Exception)
            {
                MessageBox.Show("识别失败");
            }
            return ret;
        }
    }

最后

该工具包不能添加图标，若想添加图标可以自行渲染，或者用NuGet添加QRCoder工具，它有添加图标的接口