.NET生成二維碼

隨着移動設備的快速發展，二維碼越來越大眾普及，今天給大家介紹一下我的總結：

先來兩張效果圖（左圖不帶文字說明，右圖帶文字說明）

1. 從Nuget上找到這一個程序包（這個程序包兼容.net framework 4.7和.net core，之前引用過其他的程序包，發現並不兼容.net framework 4.7）

2.我重載了一個方法GenerateQRCode，用於生成帶文字說明和不帶文字說明的二維碼。不帶文字說明的二維碼大小尺寸沒有加限制，返回的是原始大小，帶文字說明的二維碼大小限制為了600*600px（包括文字，可以根據需要自行調整），同時，我將二維碼的文字說明放在了二維碼的下面（當然了，文字位置也是可以自行調整的，后續有時間我會繼續補充）

using QRCoder;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace App.Common.QRCode
{
    /// <summary>
    /// 二維碼幫助類
    /// </summary>
    public class QRCodeHelper
    {
        /// <summary>
        /// 生成二維碼圖片
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public Bitmap CreateQRimg(string str)
        {
            QRCodeGenerator qrGenerator = new QRCodeGenerator();
            QRCodeData qrCodeData = qrGenerator.CreateQrCode(str, QRCodeGenerator.ECCLevel.Q);
            QRCoder.QRCode qrCode = new QRCoder.QRCode(qrCodeData);
            Bitmap bt = qrCode.GetGraphic(20);

            return bt;
        }

        /// <summary>
        /// 生成二維碼圖片流（二維碼上含文字）
        /// </summary>
        /// <param name="str1">二維碼中要傳遞的數據（地址）</param>
        /// <param name="str2">二維碼上顯示的文字說明</param>
        public byte[] GenerateQRCode(string str1, string str2)
        {
            using (Image codeImage = CreateQRimg(str1), strImage = ConvertStringToImage(str2))
            {
                Image img = CombineImage(600, 600, codeImage, 60, 50, strImage, 0, 530);
                using (var stream = new MemoryStream())
                {
                    img.Save(stream, ImageFormat.Jpeg);
                    //輸出圖片流
                    return stream.ToArray();
                }
            }
        }

        /// <summary>
        /// 生成二維碼圖片流（不含文字）
        /// </summary>
        /// <param name="str">二維碼中要傳遞的數據（地址）</param>
        /// <returns></returns>
        public byte[] GenerateQRCode(string str)
        {
            using (Image codeImage = CreateQRimg(str))
            {
                using (var stream = new MemoryStream())
                {
                    codeImage.Save(stream, ImageFormat.Jpeg);

                    return stream.ToArray();
                }
            }
        }

        /// <summary>
        /// 生成文字圖片
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public Image ConvertStringToImage(string str)
        {
            Bitmap image = new Bitmap(600, 40, PixelFormat.Format24bppRgb);

            Graphics g = Graphics.FromImage(image);

            try
            {
                Font font = new Font("SimHei", 14, FontStyle.Regular);

                g.Clear(Color.White);

                StringFormat format = new StringFormat();
                format.Alignment = StringAlignment.Center;
                format.LineAlignment = StringAlignment.Center;

                Rectangle rectangle = new Rectangle(0, 0, 600, 40);

                g.DrawString(str, font, new SolidBrush(Color.Black), rectangle, format);

                return image;
            }
            catch (Exception e)
            {
                throw e;
            }
            finally
            {
                GC.Collect();
            }
        }

        /// <summary>
        /// 在畫板中合並二維碼圖片和文字圖片
        /// </summary>
        /// <param name="width"></param>
        /// <param name="height"></param>
        /// <param name="imgLeft"></param>
        /// <param name="imgLeft_left"></param>
        /// <param name="imgLeft_top"></param>
        /// <param name="imgRight"></param>
        /// <param name="imgRight_left"></param>
        /// <param name="imgRight_top"></param>
        /// <returns></returns>
        public Image CombineImage(int width, int height, Image imgLeft, int imgLeft_left, int imgLeft_top, Image imgRight, int imgRight_left, int imgRight_top)
        {
            Bitmap image = new Bitmap(width, height, PixelFormat.Format24bppRgb);

            Graphics g = Graphics.FromImage(image);

            try
            {
                g.Clear(Color.White);
                g.DrawImage(imgLeft, imgLeft_left, imgLeft_top, 500, 500);
                g.DrawImage(imgRight, imgRight_left, imgRight_top, imgRight.Width, imgRight.Height);

                return image;
            }
            catch (Exception e)
            {
                throw e;
            }
            finally
            {
                g.Dispose();
            }
        }
    }
}

最后，再補充兩個調用方法

/// <summary>
    /// Mvc
    /// </summary>
    public class QRCodeController : Controller
    {
        /// <summary>
        /// 顯示二維碼
        /// </summary>
        /// <returns></returns>
        public ActionResult Index()
        {
            var qrCode = new QRCodeHelper();
            var qrImg = qrCode.GenerateQRCode("https://www.cnblogs.com/wenha");
            
            var base64 = "data:image/jpeg;base64," + Convert.ToBase64String(qrImg);

            ViewBag.CodeImg = base64;
            return View();
        }
    }

/// <summary>
    /// WebApi
    /// </summary>
    public class QRCodeApiController : ApiController
    {
        /// <summary>
        /// 獲取二維碼圖片（base64格式）
        /// </summary>
        /// <returns></returns>
        [HttpGet]
        public HttpResponseMessage GetQRCode()
        {
            var qrCode = new QRCodeHelper();

            var url = "https://www.cnblogs.com/wenha";
            var image = qrCode.GenerateQRCode(url, "博客園地址");

            var resp = new HttpResponseMessage(HttpStatusCode.OK)
            {
                Content = new StringContent("data:image/jpeg;base64," + Convert.ToBase64String(image))
            };

            return resp;
        }

        /// <summary>
        /// 獲取二維碼圖片（圖片格式）
        /// </summary>
        /// <returns></returns>
        [HttpGet]
        public HttpResponseMessage GetQRCodeImg()
        {

            var qrCode = new QRCodeHelper();

            var url = "https://www.cnblogs.com/wenha";
            var image = qrCode.GenerateQRCode(url, "博客園地址");

            var resp = new HttpResponseMessage(HttpStatusCode.OK)
            {
                Content = new ByteArrayContent(image)
            };
            resp.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpg");
            return resp;
        }
    }