Question

I am having some problems with my gallery. First I download all thumbnails for an overview. But when I click on a picture, first I want to show the thumbnail and load the big picture. When this is done, I want to change the ImageSource to the new picture. Here is my example:

    private BitmapImage picture;   
    public BitmapImage Picture
    {
        get
        {
            if (picture == null)
            {
                RequestBigpicture();
                return Thumbnail;
            }
            return picture;
        }
    }   

    public void RequestBigpicture()          
    {
        picture = new BitmapImage(new Uri("http://www.fun-hollywood.de/" + bigPicture, UriKind.Absolute));
        picture.ImageOpened += pictureImage_ImageOpened;
    }

    void pictureImage_ImageOpened(object sender, System.Windows.RoutedEventArgs e)
    {
        NotifyPropertyChanged("Picture");
    }

This was not working, also this part (as I read somewhere) in RequestBitPicture is not better:

        picture = new BitmapImage(new Uri("http://www.fun-hollywood.de/" + bigPicture, UriKind.Absolute));
        var pictureImage = new Image();
        pictureImage.Source = picture;
        pictureImage.ImageOpened += pictureImage_ImageOpened;

The ImageOpened is never called. How would be the best way to do this?

Answer 1

I think you should set the BitmapImage.CreateOptions property to None or to BackgroundCreation to instantly trigger the image download.
Because the default value is DelayCreation that is why your image won’t donwloaded and the ImageOpened event is never fired.