效果如下：

1.创建一个winform的窗体项目（框架.NET Framework 4.7.2）
2.Nuget引入opencv的c#程序包（版本最好和我一致）

3.后台代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
using OpenCvSharp;
using OpenCvSharp.Extensions;namespace opencv读取摄像头
{public partial class Form1 : Form{public Form1(){InitializeComponent();Control.CheckForIllegalCrossThreadCalls = false;//取消跨线程检查this.timer1.Start();}private VideoCapture capture;private bool isopen = false;private bool saveImgFlag = false;private string filePath = "";private void button1_Click(object sender, EventArgs e){capture = new VideoCapture(0);if (!capture.IsOpened()){MessageBox.Show("无法打开摄像头");return;}isopen = true;Thread video_th = new Thread(StartCapturing);video_th.IsBackground = true;video_th.Start();}public void StartCapturing(){Mat frame = new Mat();while (true){capture.Read(frame);//读取图像帧if (frame.Empty()){break;}Bitmap bitmap = BitmapConverter.ToBitmap(frame);if (saveImgFlag == true){try{bitmap.Save(filePath, ImageFormat.Jpeg);saveImgFlag = false;MessageBox.Show("保存成功！");}catch (Exception ex){}}pictureBox1.Image = bitmap;pictureBox1.Refresh();}}private void button2_Click(object sender, EventArgs e){SaveFileDialog saveFileDialog = new SaveFileDialog();// 设置对话框的标题saveFileDialog.Title = "Save Image";// 设置默认的文件名和文件类型过滤器saveFileDialog.FileName = DateTime.Now.ToString("yyyy_MM_dd_HH_mm_ss");saveFileDialog.Filter = "Image files (*.Png)|*.Png|Image files (*.Jpg)|*.Jpg";// 显示对话框并获取用户的操作结果DialogResult result = saveFileDialog.ShowDialog();if (result == DialogResult.OK){// 用户点击了保存按钮filePath = saveFileDialog.FileName;//string filter=saveFileDialog.Filter;// 在这里进行保存文件的操作，例如：// File.WriteAllText(filePath, "Hello, world!");Console.WriteLine("File saved to: " + filePath);}else if (result == DialogResult.Cancel){// 用户点击了取消按钮Console.WriteLine("Save cancelled");}saveImgFlag = true;}private void timer1_Tick(object sender, EventArgs e){this.label1.Text = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");}}
}