Huge memory usage in Xamarin

Question

I have some problems running my app on some old Androiddevices, and I therefore downloaded a trail of Visual Studio Professionel, as it has Diagnostics Tools.

I tried doing some simple stuff in my app, and I find it is scaring, that Xamarin.Forms.BindableProperty+BindablePropertyContext takes a size (in bytes of course) of 2.196.088 in UWP, which you can see at the following screendump.

.

In the example I have justed navigated through 5 pages. On 2 of the pages there are ListViews, and one of them have been cleared 3 times, and filled with new data.

So do I have to call GC.Collect() after clearing the ListView?

Answer 1

I've had a similar issue - navigating through pages a couple of times caused an OutOfMemoryException. For me the solution was to implement custom render for page with explicit Dispose() call.

public class CustomPageRenderer : PageRenderer
{
    private NavigationPage _navigationPage;

    protected override void OnElementChanged(ElementChangedEventArgs<Page> e)
    {
        base.OnElementChanged(e);
        _navigationPage = GetNavigationPage(Element);
        SubscribeToPopped(_navigationPage);
    }

    private void SubscribeToPopped(NavigationPage navigationPage)
    {
        if (navigationPage == null)
        {
            return;
        }

        navigationPage.Popped += OnPagePopped;
    }

    protected override void Dispose(bool disposing)
    {
        Log.Info("===========Dispose called===========");
        base.Dispose(disposing);
    }

    private void OnPagePopped(object sender, NavigationEventArgs args)
    {
        if (args.Page != Element)
        {
            return;
        }

        Dispose(true);
        _navigationPage.Popped -= OnPagePopped;
    }

    private static NavigationPage GetNavigationPage(Element element)
    {
        if (element == null)
        {
            return null;
        }

        while (true)
        {
            if (element.Parent == null || element.Parent.GetType() == typeof(NavigationPage))
            {
                return element.Parent as NavigationPage;
            }

            element = element.Parent;
        }
    }
}

You can also take a look here but you need to be careful with disposing images, it may cause some problems if their parent page is in navigation stack and you want to go back.