ShareTarget only shows splash screen

[Arko109]

When sharing to an app with ShareTarget feature, only the app's splash screen is displayed (not the ShareTarget page).

Here's how I navigate to it in App.xaml.cs (I use Prism):

protected override async void OnShareTargetActivated(ShareTargetActivatedEventArgs args)
{
    base.OnShareTargetActivated(args);
    await InitializeFrameAsync(args);
    await LaunchApplicationAsync("ShareTarget", args.ShareOperation);
}

Additionally, when closing the window, the app crashes.

Am I doing something wrong?

[mvegaca]

Hi.

Activation from ShareTarget opens the app as a new modal window, so you can add this code on App.xaml.cs to show the shared content in the modal window.

protected override async void OnShareTargetActivated(ShareTargetActivatedEventArgs args)
{
    base.OnShareTargetActivated(args);
    var rootFrame = await InitializeFrameAsync(args);
    rootFrame.Navigate(typeof(ShareTargetPage), args.ShareOperation);
    Window.Current.Content = rootFrame;
    Window.Current.Activate();
}

The app still crashes when you close the modal window. I think this is related with a Prism threading issue.

[Arko109]

Hi, thank you for your reply. The ShareTarget page is displayed now.

I already had a problem with an app crashing on close, it was because the navigation parameter needs to be serializable. Maybe this is the problem here too.

[sibille]

@Arko109, were you able to fix the param serialization issue?

[Arko109]

@sibille no, I tried to serialize the SharedOperation with Json.NET but it is impossible to deserialize it later, because it has no constructor.

In the previous case I mentioned, I was able to solve the problem like this:

In App.xaml.cs:

rootFrame.Navigate(typeof(ShareTargetPage), JsonConvert.SerializeObject(args.ShareOperation));

And in ShareTargetPage.xaml.cs:

await ViewModel.LoadAsync(JsonConvert.DeserializeObject<ShareOperation>(e.Parameter as string));

However, in this case I am getting this exception:

Newtonsoft.Json.JsonSerializationException: 'Unable to find a constructor to use for type Windows.ApplicationModel.DataTransfer.ShareTarget.ShareOperation. A class should either have a default constructor, one constructor with arguments or a constructor marked with the JsonConstructor attribute. Path 'Data', line 1, position 8.'

[sibille]

@Arko109, I don't think serialization is the problem, I tried to pass a simple string as argument and got the same exception. I've opened an issue on the prism github to see if we can get some help there.

[bartlannoeye]

We've always promoted using value types as navigation parameter (and retrieve the object from your manager/service/…) to keep backstack small and work around serialization issues (which date back to .NET Native issues). But since @sibille tried with a string, it's probably something else. I'll do my best to dig up the code and have a look at it this weekend.

[sibille]

@bartlannoeye, did you have the chance to look at this? @LucasHaines, I think we should hide this feature in 3.6 until we fix it.