How to Dispose the MediaElement in .NET 8?

[marco-skizza]

Hi

As it seems, the Unloaded event of a page was wrongly implemented in .NET 7 - where it was called when the page was "destroyed". This seems to be fixed now in .NET 8 and the Unloaded event gets called whenever the page exits the visual tree.

See also:
dotnet/maui#16697

In .NET 8 and iOS I now have the problem, that this Unloaded event even gets called when entering the fullscreen mode in the MediaElement. So disposing the resources in this event is no option anymore.

See also the docu of MediaElement:
https://learn.microsoft.com/en-us/dotnet/communitytoolkit/maui/views/mediaelement#clean-up-mediaelement-resources

So what's the recommended way to clean up the resources of a MediaElement in .NET 8?

[pictos]

@marco-skizza you can try to override the OnNavigatedFrom method, hopefully going to full screen mode will not trigger the Navigated event

[pictos]

@PureWeen I mean, the fact that on WIndows the handler is never null when the OnHandlerChanging is fired

[marco-skizza]

Hi

A summary of my findings so far...

The Unloaded is now called on iOS when leaving the page as described above.
So one can currently use the following on iOS:

    protected override void OnHandlerChanging(HandlerChangingEventArgs args)
    {
        base.OnHandlerChanging(args);

        if (args.NewHandler != null)
        {
            return;
        }

        MyMediaElement.Handler?.DisconnectHandler();
        MyMediaElement.Dispose();
    }

On Android it seems to behave the same way as in .NET 7.
So one can use the following on Android as before:

    private void OnUnloaded(object? sender, EventArgs e)
    {
        MyMediaElement.Handler?.DisconnectHandler();
        MyMediaElement.Dispose();
    }

For WinUI I haven't found a solution so far.

P.S.:
Note the additional call to MyMediaElement.Dispose();.
This is according to my findings in: #1702

[pictos]

@marco-skizza we just released a new version of Media element, can you try that and see if it's better?

[marco-skizza]

@pictos

Yes, it works!
The memory leak is gone with the new version, when disposing the MediaElement as shown above.
Many thanks for all your effort!

[bzd3y]

I know this was closed, but I think there is more going on here, at least on Android. This may have to do with Maui in general, and not the MediaElement. But with that being said, I am still unclear on how to properly dispose the MediaElement.

In my situation, Unloaded is not being called on "leaving" the page, but that may be because I have pages being pushed to the navigation stack. But in that case, if I push the next page on the navigation stack and then return to the previous page that contained the MediaElement that is when Unloaded gets called, but it gets called twice. The first call disposes the MediaElement as above, and then the second call does nothing because it is already disposed.

But it gets even weirder, because in this case the "back" feature of app I maintain doesn't pop from the navigation stack. For reasons that aren't relevant here (though I am looking into changing this behavior anyway), the app recreates the previous page and pushes that onto the navigation stack (the app maintains its own stack of the content that has been displayed and uses that to go back).

And so considering that, I am confused as to why Unloaded was called at all, because the previous loaded view should still be on the navigation stack and continue to be "loaded", shouldn't it?

When the previous page is recreated, at least one of the Unloaded calls (I believe the first) is being called on the newly pushed view and so the MediaElement on that view has been disposed and is non-functional.

I'm guessing this is all due to Maui reusing views to optimize things or something like that. But if that is the case, then Unloaded seems like it cannot be relied on to dispose a MediaElement like this.

Further, from what I can tell, OnHandlerChanging doesn't get called with a null NewHandler at all during this process on Android, like it does on iOS, even after popping everything off of the navigation stack or manually disconnecting the handler like in the above answer.

[CliffAgius]

Closed as answered