Binding Image URIs via Image.SetBinding() not working properly - forms

Question

I'm using the following code snippet to bind a image url to a image object (used as one element in a ViewCell object).
...
Image Picture = new Image()
{
Aspect = Aspect.AspectFit,
HorizontalOptions = LayoutOptions.StartAndExpand
}; // ImageSource.FromUri(new Uri("sImageUrl")))
Picture.SetBinding(Image.SourceProperty, "sImageUrl");
...
The images in the list, for which I'm using that cell view, are not loading always. I was not able to identify the exact reason for the problem, but I think the problem is the load-process (for loading the images from the url/internet)..
Maybe the problem could be solved by setting the url via new Uri(...) as described in the documentation
var webImage = new Image { Aspect = Aspect.AspectFit };
webImage.Source = ImageSource.FromUri(new Uri("https://xamarin.com/content/images/pages/forms/example-app.png"));
Now my question: is there a workaround for binding a uri object? e.g.
...
Image Picture = new Image()
{
Aspect = Aspect.AspectFit,
HorizontalOptions = LayoutOptions.StartAndExpand
}; // ImageSource.FromUri(new Uri("sImageUrl")))
Picture.SetBinding(Image.SourceProperty, ImageSource.FromUri(new Uri("sImageUrl")));
...
I'm working with xamarin studio (version 6.1.2, build 44, update channel "beta", os x).
Would be great if someone got a tipp.
Thanks a lot,
Alex

Answer 1

after some more trying I found a solution.. I'm not sure if it's a secure / professional way.. But for now, it seems to work.
What I did: I implemented my own class "AsyncSrcImage", derived it from Image and added another bindable property:
public class AsyncSrcImage : Image
{
private static String sDefaultURL = "";
public static readonly BindableProperty AsyncImgUrlProperty = BindableProperty.Create(nameof(AsyncImgUrl), typeof(String), typeof(AsyncSrcImage), sDefaultURL);
public String AsyncImgUrl
{
get { return (String)GetValue(AsyncImgUrlProperty); }
set { SetValue(AsyncImgUrlProperty, value); }
}
}
Additionally I adjusted the rendering process with a custom renderer. There I'm loading the image source via new Uri(...) as described in the documentation:
using Xamarin.Forms.Platform.Android;
using Xamarin.Forms;
using System;
[assembly: ExportRenderer(typeof(AsyncSrcImage), typeof(AsyncSrcImageRenderer))]
public class AsyncSrcImageRenderer : ImageRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Image> e)
{
base.OnElementChanged(e);
AsyncSrcImage oImage = (AsyncSrcImage)Element;
if (oImage != null && oImage.AsyncImgUrl != "")
{
oImage.Source = ImageSource.FromUri(new Uri(oImage.AsyncImgUrl));
}
}
}
Maybe that helps other folks ;)