c# 使用AForge.NET操作摄像头操作代码
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;      
            }  
        }         
    }  
}