如何使用c#中的网格包围网络摄像头

本文关键字：包围 网络 摄像头 网格 何使用 | 更新日期: 2023-09-27 17:58:25

我正在使用Forge.NET库用c#制作一个网络摄像头，我想打开网络摄像头拍一张rubix立方体的照片。我用一个图片框来处理网络摄像头的框架，我想在图片框内制作一个网格3*3。

它可以工作，但运行3秒后会生成一个异常：

g = Graphics.FromImage(videoBox.Image);  ----> InvalidOperationException

这是我的代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using AForge.Video;
using AForge.Video.DirectShow;
namespace WebcamTester
{
    public partial class Form1 : Form
    {
        public Form1()
        {
        InitializeComponent();
        }
    private FilterInfoCollection webcam;
    private VideoCaptureDevice cam;
    private Bitmap bit = new Bitmap(640, 480);
    private Graphics g;
    private int cellsNumber;
    private int cellSize;
    private void Form1_Load(object sender, EventArgs e)
    {
        webcam = new FilterInfoCollection(FilterCategory.VideoInputDevice);
        foreach (FilterInfo VideoCaptureDevice in webcam)
        {
            comboBox1.Items.Add(VideoCaptureDevice.Name);
        }
        comboBox1.SelectedIndex = 0;
        cam = new VideoCaptureDevice(webcam[comboBox1.SelectedIndex].MonikerString);
        cam.NewFrame += new NewFrameEventHandler(cam_NewFrame);
        cam.Start();
    }

    void cam_NewFrame(object sender, NewFrameEventArgs eventArgs)
    {
        bit = (Bitmap)eventArgs.Frame.Clone();
        videoBox.Image = bit;
        g = Graphics.FromImage(videoBox.Image);
        Pen p = new Pen(Color.Black, 2);
        cellSize = 100;
        cellsNumber = 4;
        for (int y = 0; y <= cellsNumber; ++y)
        {
            g.DrawLine(p, 0, y * cellSize, cellsNumber * cellSize, y * cellSize);
        }
        for (int x = 0; x <= cellsNumber; ++x)
        {
            g.DrawLine(p, x * cellSize, 0, x * cellSize, cellsNumber * cellSize);
        }
    }
    private void button2_Click(object sender, EventArgs e)
    {
        saveFileDialog1.InitialDirectory = @"d:'picture";
        cam.Stop();
        if (saveFileDialog1.ShowDialog() == DialogResult.OK)
        {
            videoBox.Image.Save(saveFileDialog1.FileName);
            cam.Start();
        }
        else
            cam.Start();
    }
}

}

如何使用c#中的网格包围网络摄像头

此异常与对象当前在其他地方使用有关也许是因为没有发布。。。

你应该试试：

    (...)
    for (int x = 0; x <= cellsNumber; ++x)
    {
        g.DrawLine(p, x * cellSize, 0, x * cellSize, cellsNumber * cellSize);
    }
    g.Dispose();
}

如果这没有帮助，您应该尝试使用

private object Lock = new object();
  lock (Lock) {
      using (var g = Graphics.FromImage(videoBox.Image) {  
        Pen p = new Pen(Color.Black, 2);
        cellSize = 100;
        cellsNumber = 4;
        for (int y = 0; y <= cellsNumber; ++y)
        {
            g.DrawLine(p, 0, y * cellSize, cellsNumber * cellSize, y * cellSize);
        }
        for (int x = 0; x <= cellsNumber; ++x)
        {
            g.DrawLine(p, x * cellSize, 0, x * cellSize, cellsNumber * cellSize);
        }
        g.Dispose();
     }        
  }
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