How to display a downloaded image in WPF window

Question

I need to download a webcam image thru http, and refresh it at 10fps and display it on a WPF window. Right now I'm using this code:

    Window1 wndMain;
    BitmapImage img;
    DispatcherTimer tmrRefresh;
    public WCam(Window1 wndMain, string imguri)
    {
        this.wndMain = wndMain;
        this.MouseLeftButtonDown += delegate { DragMove(); };
        url = imguri;
        InitializeComponent();
        tmrRefresh = new DispatcherTimer(TimeSpan.FromMilliseconds(100),
        DispatcherPriority.Normal, Refresh, Dispatcher.CurrentDispatcher);
    }

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        if (url != "")
        {
            try
            {
                img = new BitmapImage();
                img.BeginInit();
                img.CacheOption = BitmapCacheOption.OnLoad;
                img.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
                img.UriSource=(new Uri(url));
                img.EndInit();
            }
            catch (Exception ex)
            {
                new WPopup().Show(ex.Message);
            }
            ImgBox.Source = img;
            tmrRefresh.Start();
        }

    }
    public void Refresh(object sender, EventArgs e)
    {
        try
        {
            img = new BitmapImage();
            img.BeginInit();
            img.CacheOption = BitmapCacheOption.OnLoad;
            img.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
            img.UriSource = (new Uri(url));
            img.EndInit();
        }
        catch (Exception ex)
        {
            new WPopup().Show(ex.Message);
        }
        ImgBox.Source = null;
        ImgBox.Source = img;
    }

It displays nothing, if I increase the timer interval to 1000 it displays images but the image goes away while it loads the next one. Also the window loads in awfully slowly.

Answer 1

Seperate the loading logic from the image. Keep the loaded code as is, the refresh should download the image with a simple async(to keep ui running) request and only when finished change the image source to the local memory.