Allow `Shell.Current.DisplayPromptAsync` to be cancelled with a `CancellationTokenSource`

[AndreasReitberger]

Description

I have a usecase, where a prompt is displayed and an input is required. If the input doesn't happen in a specified time, the prompt should close and return null.

Public API Changes

await Shell.Current.DisplayPromptAsync(
"Input Unit",
"Waiting for robo to input the Unit.", x,x,x,
new CancellationTokenSource(TimeSpan.FromSeconds(30))
)

Intended Use-Case

When a CancellationTokenSource is passed, and it's cancled (by timeout or whatever), the prompt should be closed and return null or an empty string.

[pictos]

@AndreasReitberger you can use the new extension method called .WaitAsync, that should work.

await Shell.Current.DisplayPromptAsync("f", "f").WaitAsync(new CancellationTokenSource(TimeSpan.FromSeconds(30)).Token);

[rachelkang]

Hi, @AndreasReitberger - I see you heart reacted to the above comment. Can you confirm that @pictos' suggestion worked for you and that this issue can be closed? Thanks :)

Hi @AndreasReitberger. We have added the "s/needs-info" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[AndreasReitberger]

@rachelkang
From what I can see, this should work. However I haven't tested yet. I'll do so tomorrow and close the issue if the suggestion works as intended 😃

Thank you @pictos

[AndreasReitberger]

Hi @pictos @rachelkang

I tried the script, however it does not fully work as expected.

Dispatcher.DispatchAsync(async () =>
{
	try
	{
		var CustomerSerialNumber = await Shell.Current.DisplayPromptAsync(
			"Input Custom Serial Number",
			"Waiting for robo to input the serial number."
			)
		// Cancel after 30 seconds of no respones
		.WaitAsync(new CancellationTokenSource(TimeSpan.FromSeconds(30)).Token);
	}
	catch(Exception ex)
	{

	}
});

The Task gets cancelled after the 30 seconds, however the prompt is still shown and available for input. It actually should close and return null, or at least disappear if the Exception gets thrown. Or is there anything I do wrong?

Thank you!

[janseris]

Hi, @AndreasReitberger - I see you heart reacted to the above comment. Can you confirm that @pictos' suggestion worked for you and that this issue can be closed? Thanks :)

This needs to be built in as a standard API with CancellationToken support.
I doubt anyone will come up with a random solution like that out of the box.

For example that the API with CancellationToken would just call the suggested function in the background, or anything simple but standard in the public API.