我正在尝试使用Microsoft Lifecam开发一个winform应用程序，我需要使用网络摄像头捕获视频并尝试使用Aforge将视频保存到文件夹。
构建编译成功但每次运行应用程序时。它会抛出错误
＆＃34;未处理的类型＆＃39; System.NullReferenceException＆＃39; 发生在System.Drawing.dll
中附加信息：对象引用未设置为的实例 。对象＆＃34;
我无法弄清楚弹出此错误的原因。
完整的代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using AForge;
using AForge.Video;
using AForge.Video.DirectShow;
using AForge.Video.FFMPEG;
using AForge.Video.VFW;
using System.Drawing.Imaging;
using System.IO;
using Microsoft.LifeCam.Controllers;
using Microsoft.LifeCam.WebCam;
using Microsoft.LifeCam.Framework;
using Microsoft.LifeCam.Application;
using Microsoft.LifeCam.Interfaces;
using Microsoft.LifeCam;
namespace webcam_application
{
public partial class Form1 : Form
{
private FilterInfoCollection integratedcamera;
private VideoCaptureDevice capturedevice;
private VideoCaptureDeviceForm capturedevice1;
private VideoCaptureDevice final_video = new VideoCaptureDevice();
private VideoFileWriter FileWriter = new VideoFileWriter();
private SaveFileDialog saveavi;
private Bitmap video;
public Bitmap Video
{
get
{
return video;
}
set
{
video = value;
}
}
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
integratedcamera = new FilterInfoCollection(FilterCategory.VideoInputDevice);
foreach (FilterInfo device in integratedcamera)
{
comboBox1.Items.Add(device.Name);
}
comboBox1.SelectedIndex = 0;
capturedevice = new VideoCaptureDevice();
capturedevice1 = new VideoCaptureDeviceForm();
capturedevice = new VideoCaptureDevice(integratedcamera[comboBox1.SelectedIndex].MonikerString);
capturedevice.NewFrame += new NewFrameEventHandler(Finalframe_Newframe);
capturedevice.Start();
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
closecamera();
}
private void button1_Click(object sender, EventArgs e)
{
capturedevice = new VideoCaptureDevice(integratedcamera[comboBox1.SelectedIndex].MonikerString);
capturedevice.NewFrame += new NewFrameEventHandler(Finalframe_Newframe);
capturedevice.Start();
}
void Finalframe_Newframe(object sender, NewFrameEventArgs eventArgs)
{
Bitmap video = (Bitmap)eventArgs.Frame.Clone();
pictureBox1.Image = video;
}
private void Form1_FormClosed(object sender, FormClosedEventArgs e)
{
closecamera();
}
void closecamera()
{
if (capturedevice != null)
{
if (capturedevice.IsRunning == true)
{
capturedevice.Stop();
pictureBox1.Image = new Bitmap(640, 480);
}
}
}
private void pictureBox1_Click(object sender, EventArgs e)
{
}
private void button2_Click(object sender, EventArgs e)
{
if (capturedevice1.ShowDialog(this) == DialogResult.OK)
{
VideoCaptureDevice videoSource = capturedevice1.VideoDevice;
final_video = capturedevice1.VideoDevice;
final_video.NewFrame += Final_video_NewFrame;
final_video.Start();
}
}
private void Final_video_NewFrame(object sender, NewFrameEventArgs eventArgs)
{
video = (Bitmap)eventArgs.Frame.Clone();
pictureBox1.Image = (Bitmap)eventArgs.Frame.Clone();
FileWriter.WriteVideoFrame(video);
}
private void button3_Click(object sender, EventArgs e)
{
saveavi = new SaveFileDialog();
saveavi.Filter = "Avi Files (*.avi)|*.avi";
if (saveavi.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
int h = capturedevice1.VideoDevice.VideoResolution.FrameSize.Height;
int w = capturedevice1.VideoDevice.VideoResolution.FrameSize.Width;
FileWriter.Open(saveavi.FileName, w, h, 25, VideoCodec.Default, 5000000);
// Bitmap abc = new Bitmap(video);
FileWriter.WriteVideoFrame(video);
if (final_video.IsRunning)
{
FileWriter.Close();
final_video.SignalToStop();
//this.FinalVideo.Stop();
//this.AVIwriter.Close();
pictureBox1.Image = null;
}
}
}
}
}