Question

I am a beginner. How and where should i put a label messages after a video is created from below code.

I want to display two messages after the process is completed which is label1: video was created successfully and 2nd messages is videopath of the video.

I only want to display it after the process is completed(video was created).

namespace test
{
    public partial class liveRecording : System.Web.UI.Page
    {
    //video codec
    AVIWriter writer = new AVIWriter("MSVC");  

    protected void Page_Load(object sender, EventArgs e)
    {
        string streamingSource = "http://xxx.sample.com:85/snapshot.cgi";
        string login = "login";
        string password = "password";

        JPEGStream JPEGSource = new JPEGStream(streamingSource);
        JPEGSource.Login = login;
        JPEGSource.Password = password;
        JPEGSource.NewFrame += new NewFrameEventHandler(video_NewFrame);
        JPEGSource.Start();
    }

    public bool IsRecording = false;
    int width = 0;
    int height = 0;

    Queue<Bitmap> frames = new Queue<Bitmap>(); //Queue that store frames to be written by the recorder thread

    private void video_NewFrame(object sender, NewFrameEventArgs eventArgs) //event handler for NewFrame
    {
        //get frame from JPEGStream source
        //Bitmap image = eventArgs.Frame;
        Bitmap image = (Bitmap)eventArgs.Frame.Clone(); //get a copy of the Bitmap from the source

        width = image.Width;
        height = image.Height;

        if (IsRecording)
        {
            //enqueue the current frame to be encoded to a video file
            frames.Enqueue((Bitmap)image.Clone());
        }

        if (!IsRecording)
        {
            IsRecording = true;
            Thread th = new Thread(DoRecording);
            th.Start();
        }
    }

    private void DoRecording()
    {
        //writer.FrameRate = 5;
        string SavingPath = (Server.MapPath("~\\video\\")); 
        string VideoName = "ICS_" + String.Format("{0:yyyyMMdd_hhmmss}", DateTime.Now) + ".avi";
        writer.Open(SavingPath + VideoName, width, height);

        DateTime start = DateTime.Now;
        while (DateTime.Now.Subtract(start).Seconds < 30)
        {
            if (frames.Count > 0)
            {
                Bitmap bmp = frames.Dequeue();
                writer.AddFrame(bmp);//add frames to AVI file
            }
        }
        writer.Close();//close
    }
}
}

Answer 1

I only want to display it after the process is completed(video was created).

Then you should use AJAX, basically. Your “start encoding” (or whatever) request should complete quickly, so the user gets an appropriate page back. That page should contain Javascript to regularly poll the server to see whether the task has completed – you’ll need some coordination (e.g. via a randomly generated “job ID” which is provided to the client). You could use something like SignalR for “long polling” (where the AJAX fires a request which is expected to wait until either the job has completed or it times out) or just make a quick polling request every few seconds.

I’m afraid none of this is easy if you’re new to web development – but the task you’re trying to perform isn’t easy, in a world based on HTTP requests and responses.