C# 从 Windows 服务监控桌面屏幕

Question

I have just written the C# Code that is recording the screenshot of the desktop.It works on Winforms but not works in windows service.

My code as below:

public partial class ScreenCapture : ServiceBase
{
        bool rec = false;

        Rectangle screenSize = Screen.PrimaryScreen.Bounds;

        UInt32 frameCount = 0;

        VideoFileWriter writer;

        int width = SystemInformation.VirtualScreen.Width;
        int height = SystemInformation.VirtualScreen.Height;

        AForge.Video.ScreenCaptureStream streamVideo;

        Stopwatch stopWatch = new Stopwatch();

        public ScreenCapture()
        {
            InitializeComponent();
            writer = new VideoFileWriter();
            if (!System.Diagnostics.EventLog.SourceExists("MySource"))
            {
                System.Diagnostics.EventLog.CreateEventSource("MySource", "MyLog");
            }
            eventLog1.Source = "MySource";
            this.CanHandleSessionChangeEvent = true;
        }

        protected override void OnSessionChange(SessionChangeDescription changeDescription)
        {
            string folderName = @"C:\LoginLog";
            if (changeDescription.Reason == SessionChangeReason.SessionLogon)
            {
                eventLog1.WriteEntry(changeDescription.SessionId + " User Logon");
                if (!Directory.Exists(folderName))
                {
                    Directory.CreateDirectory(folderName);
                }

                StartRec(folderName);
            }
            else if (changeDescription.Reason == SessionChangeReason.SessionLogoff)
            {
                eventLog1.WriteEntry(changeDescription.SessionId + " User Logoff");
                rec = false;
            }
            else if (changeDescription.Reason == SessionChangeReason.SessionLock)
            {
                eventLog1.WriteEntry(changeDescription.SessionId + " User Lock");
                rec = false;
            }
            else if (changeDescription.Reason == SessionChangeReason.SessionUnlock)
            {
                eventLog1.WriteEntry(changeDescription.SessionId + " User Unlock");
                if (!Directory.Exists(folderName))
                {
                    Directory.CreateDirectory(folderName);
                }

                StartRec(folderName);
            }
            base.OnSessionChange(changeDescription);
        }

        private void StartRec(string path)
        {
            if (rec == false)
            {
                rec = true;

                frameCount = 0;

                string time = DateTime.Now.ToString("yyyy_MM_dd_HH_mm_ssff");
                string compName = Environment.UserName;
                string fullName = path + "\\" + compName.ToUpper() + "_" + time;

                try
                {
                    writer.Open(
                        fullName + ".mp4",
                        width,
                        height,
                        10,
                        VideoCodec.MPEG4, 1000000);
                }
                catch (Exception ex)
                {
                    eventLog1.WriteEntry("Exception StartRec: " + ex.Message);
                }

                DoJob();
            }
        }

        private void DoJob()
        {
            try
            {
                Rectangle screenArea = Rectangle.Empty;
                foreach (System.Windows.Forms.Screen screen in
                    System.Windows.Forms.Screen.AllScreens)
                {
                    screenArea = Rectangle.Union(screenArea, screen.Bounds);
                }

                streamVideo = new ScreenCaptureStream(screenArea);

                streamVideo.NewFrame += new NewFrameEventHandler(video_NewFrame);

                streamVideo.Start();

                stopWatch.Start();
            }
            catch (Exception ex)
            {
                eventLog1.WriteEntry("Exception DoJob: " + ex.Message);
            }
        }

        private void video_NewFrame(object sender, AForge.Video.NewFrameEventArgs eventArgs)
        {
            try
            {
                if (rec)
                {
                    frameCount++;
                    writer.WriteVideoFrame(eventArgs.Frame);
                }
                else
                {
                    stopWatch.Reset();
                    Thread.Sleep(500);
                    streamVideo.SignalToStop();
                    Thread.Sleep(500);
                    writer.Close();
                }
            }
            catch (Exception ex)
            {
                eventLog1.WriteEntry("Exception Video New Frame: " + ex.Message);
            }
        }
}

And the service can save a .mp4 file, but it cannot open it.I think windows service can not capture desktop screen.

Can anybody help me how to solve this problem?

thanks in advance.

Answer 1

You need to set windows service run under interactive account,

To do so you need to go to properties of service got to logon tab and login by your windows account.