c# 利用AForge.NET组件操作摄像头

AForge.NET是一个专门为开发者和研究者基于C#框架设计的，这个框架提供了不同的类库和关于类库的资源，还有很多应用程序例子，包括计算机视觉与人工智能，图像处理，神经网络，遗传算法，机器学习，机器人等领域。

根据网上的方法，运行程序摄像头出来了，但是怎么截图呢？找到一个显示图片方法如下

 private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            Bitmap img = (Bitmap)eventArgs.Frame.Clone();
            //do processing here
            pictureBox1.Image = img;
        }

开始参考这句代码写了：

 private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            Bitmap img = (Bitmap)eventArgs.Frame.Clone();
            string imgPath = dirc + "/" + DateTime.Now.ToString("yyyyMMddhhmmss") + ".jpg";
            img.Save(imgPath);
        }

但是点击截图程序就自动不停截了大量的图片，最后导致程序出问题。想了一个笨方法，可以只截一次图：

 private int flag = 1;  
/// <summary>
        /// 截图
        /// </summary>
        private void toolStripButton3_Click(object sender, EventArgs e)
        {
            flag = 0;
            videoSource.NewFrame += new NewFrameEventHandler(video_NewFrame);
        }      
        private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            Bitmap bitmap = (Bitmap)eventArgs.Frame.Clone();
            if (flag == 0)
            {
                string img = dirc + "/" + DateTime.Now.ToString("yyyyMMddhhmmss") + ".jpg";
                bitmap.Save(img);
                flag = 1;    
            }
        }       

完整的程序代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;
using System.Windows.Forms;
using System.IO;
using AForge;
using AForge.Video;
using AForge.Video.DirectShow;
using AForge.Imaging;
using AForge.Imaging.Filters;

namespace Camera
{
    public partial class Form1 : Form
    {
        private FilterInfoCollection videoDevices;
        private VideoCaptureDevice videoSource;
        private int flag = 1;
        private string dirc = System.AppDomain.CurrentDomain.BaseDirectory + "Images"; //截图保存的目录
               
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            if (!Directory.Exists(dirc))
                Directory.CreateDirectory(dirc);

            try
            {
                // 枚举所有视频输入设备
                videoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);
                if (videoDevices.Count == 0)
                    throw new ApplicationException();

                foreach (FilterInfo device in videoDevices)
                {
                    tscbxCameras.Items.Add(device.Name);
                }

                tscbxCameras.SelectedIndex = 0;
            }
            catch (ApplicationException)
            {
                tscbxCameras.Items.Add("No local capture devices");
                videoDevices = null;
            }
        }

        private void toolStripButton1_Click(object sender, EventArgs e)
        {
            CameraConn();
        }

        /// <summary>
        /// 连接开启摄像头
        /// </summary>
        private void CameraConn()
        {
            videoSource = new VideoCaptureDevice(videoDevices[tscbxCameras.SelectedIndex].MonikerString);
            videoSource.DesiredFrameSize = new Size(500, 300);
            videoSource.DesiredFrameRate = 1;
            videPlayer.VideoSource = videoSource;
            videPlayer.Start();
        }
        /// <summary>
        /// 关闭摄像头
        /// </summary>
        private void toolStripButton2_Click(object sender, EventArgs e)
        {
            videPlayer.SignalToStop();
            videPlayer.WaitForStop();
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            toolStripButton2_Click(null, null);
        }
        /// <summary>
        /// 截图
        /// </summary>
        private void toolStripButton3_Click(object sender, EventArgs e)
        {
            flag = 0;
            videoSource.NewFrame += new NewFrameEventHandler(video_NewFrame);
        }      
        private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            Bitmap bitmap = (Bitmap)eventArgs.Frame.Clone();
            if (flag == 0)
            {
                string img = dirc + "/" + DateTime.Now.ToString("yyyyMMddhhmmss") + ".jpg";
                bitmap.Save(img);
                flag = 1;    
            }
        }       
    }
}

界面效果如下：