title: ObservableCollection doesnt virtualise data?
body: <p>I want to add approx 600 images to my collection to show them in a Listview that virtualizes with Itemsstackpanel. If i didnt misread with virtualization its possible to load large datasets. My problem is that the collection can only hold around 150 images and then i get a OutOfMemory Exception. <strong>Is there something more to enable virtualization or is the problem that my Collection calls its propertyChanged Event for every image added?</strong></p>
  <p>The error is thrown on:</p>
  <pre><code> await pdfPage.RenderToStreamAsync(Imagestream);
  </code></pre>
  <p>and how i add to my collection:</p>
  <pre><code>for (uint i = convertedPageString; i &lt; 200 + convertedPageString; i++)
          {
              Image img = await LoadPage(l_document, i);              
              collection.Add(img);
              g_rootPage.ListViewControl.ItemsSource = collection;
  
          }
  </code></pre>
  <p><strong>convertedPageString is just the Page im starting on when the program is opened.</strong></p>
  <p><strong>EDIT:</strong></p>
  <p>This is my function to get the Pages.</p>
  <pre><code>public async Task&lt;Image&gt; LoadPage(PdfDocument a_document, uint page)
      {
  
          Image l_image;
          BitmapImage l_bitmap;
          PdfPage pdfPage;
  
          using (IRandomAccessStream Imagestream = new MemoryStream().AsRandomAccessStream())
          {
              using (pdfPage = a_document.GetPage(page))
              {
                  
                 await pdfPage.RenderToStreamAsync(Imagestream);
  
  
              
                 l_bitmap = new BitmapImage();
                 await l_bitmap.SetSourceAsync(Imagestream);
                 l_image = new Image();
  
                  l_bitmap.DecodePixelHeight = 1200;
                  l_bitmap.DecodePixelWidth = 1000;
  
                  
                  l_image.Source = l_bitmap;
                 
                  l_image.Margin = new Thickness(0, 5, 0, 10);
                 
              }
          }
  
          return l_image; 
      }
  </code></pre>
  <p>I forgot to mention that i open the application via the commandLine with a specified page and path.</p>