C# 二维码扫描

Zint类用于产生二维码。https://sourceforge.net/projects/zint/

Zxing类用于读取二维码. https://github.com/zxing/zxing

AForge类用于初始摄像头等。http://www.aforgenet.com/framework/downloads.html

以上三个类为开源的第三方类，可直接引用。

以下为用AForge和ZXing实时读取二维码的代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using ZXing;
using ZXing.Common;
using System.Drawing.Imaging;
using AForge;
using AForge.Controls;
using AForge.Imaging;
using AForge.Video;
using AForge.Video.DirectShow;

namespace AutoScan
{
    public partial class Form1 : Form
    {
        private FilterInfoCollection videoDevices;
        private VideoCaptureDevice videoSource;
        Bitmap bmp = null; //全局变量，保存每一次捕获的图像
        int itop = 0;// 全局变量，记录扫描线距离顶端的距离
        public Form1()
        {
            InitializeComponent();
        }
        private void getVideoDevices()
        {
            cboDevices.Items.Clear();
            try
            {
                videoDevices=new FilterInfoCollection(FilterCategory.VideoInputDevice);
                if (videoDevices.Count>0)
                {
                    foreach(FilterInfo device in videoDevices)
                        cboDevices.Items.Add(device.Name);
                }
            }
            catch(Exception ex)
            {
                MessageBox.Show("not found camera");
            }
        }
        private void Open()
        {
            if (cboDevices.SelectedIndex == -1)
                return;
            try
            {
                btnOpen.Enabled = false;
                btnClose.Enabled = true;
                CloseVideoSource();
                videoSource = new VideoCaptureDevice(videoDevices[cboDevices.SelectedIndex].MonikerString);
                videoSource.DesiredFrameRate = 1;
                videoSource.DesiredFrameSize = new Size(320, 240);

                videoSource.NewFrame += new NewFrameEventHandler(newframe);
                videoSource.Start();               
            }
            catch
            {
                btnOpen.Enabled = true;
                btnClose.Enabled = false;
                return;
            }
            timer1.Enabled = true;//解析二维码
            timer2.Enabled = true;//启动绘制视频中的扫描线
        }

        private void Stop()
        {
            CloseVideoSource();
        }

        private void newframe(object sender, NewFrameEventArgs args)
        {
            bmp = (Bitmap)args.Frame.Clone();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            timer1.Enabled = false;
            timer2.Enabled = false;
            getVideoDevices();
        }
        private void CloseVideoSource()
        {
                      
            timer1.Enabled = false;
            timer2.Enabled = false;
            if (videoSource == null) return;
            if (videoSource.IsRunning)
            {
                videoSource.SignalToStop();
                videoSource.WaitForStop();
                videoSource = null;
                pictureBox1.Image = null;
            }
            btnOpen.Enabled = true;
            btnClose.Enabled = false;
            txtMsg.Clear();
        }
        private void ScanBarcode()
        {
            if (pictureBox1.Image == null)
            {
                MessageBox.Show("请载入图像资源!");
                return;
            }
            //设置读取二维码
            DecodingOptions decodeOption = new DecodingOptions();
            decodeOption.PossibleFormats = new List<BarcodeFormat>(){
                BarcodeFormat.QR_CODE
            };

            //读取操作
            BarcodeReader bar = new BarcodeReader();
            bar.Options = decodeOption;
            ZXing.Result rs = bar.Decode(pictureBox1.Image as Bitmap);
            if (rs == null)
            {
                txtMsg.Text = "读取失败";
                MessageBox.Show("读取失败");
            }
            else
            {
                txtMsg.Text = rs.Text;
                MessageBox.Show("读取成功,内容:" + rs.Text);
            }
        }

        private void timer2_Tick(object sender, EventArgs e)
        {
            timer2.Enabled = false;
            try
            {
                if (bmp == null) return;
                Bitmap bmp2 = (Bitmap)bmp.Clone();
                Pen p = new Pen(Color.GreenYellow);
                p.Width = 2;
                Graphics g=Graphics.FromImage(bmp2);
                System.Drawing.Point p1 = new System.Drawing.Point(0, itop);
                System.Drawing.Point p2 = new System.Drawing.Point(pictureBox1.Width,itop);
                g.DrawLine(p, p1, p2);
                g.Dispose();
                itop += 2;

                itop = itop % pictureBox1.Height;
                pictureBox1.Image = bmp2;
            }
            finally
            {
                timer2.Enabled = true;
            }
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            Result result;
            try
            {
                if (bmp == null) return;
                try
                {
                    BarcodeReader br = new BarcodeReader();
                    
                    result = br.Decode(bmp);                   
                }
                catch(Exception ex)
                {
                    return;
                }
                
                /*
                #region
                //将图片转换成byte数组
                MemoryStream ms = new MemoryStream();
                bmp.Save(ms, ImageFormat.Bmp);
                byte[] bt = ms.GetBuffer();
                ms.Close();

                #endregion
                LuminanceSource source = new RGBLuminanceSource(bt, bmp.Width, bmp.Height);
                BinaryBitmap bitmap = new BinaryBitmap(new ZXing.Common.HybridBinarizer(source));
                
                try
                {                  
                
                    result = new MultiFormatReader().decode(bitmap);
                }
                catch (ReaderException ex)
                {
                    return;
                }*/

                if (result != null)
                {
                    txtMsg.Text = result.Text;
                }
            }
            finally
            {
                timer1.Enabled = true;
            }          

        }

        private void btnClose_Click(object sender, EventArgs e)
        {
            CloseVideoSource();
        }

        private void btnOpen_Click(object sender, EventArgs e)
        {
            Open();
        }
    }
}

界面（黄绿色条为扫描时上下滚动的线条，把条形码放在摄像头处即可扫描）：