CODEWITHSUNDEEP
async-awaituwp
dumbledad
dumbledad

Reputation: 17527

'Task' does not contain a definition for 'AsAsyncOperation'

If I want to expose this method from a UWP class library

public async Task<int> PlaySound(SoundGroup soundGroup, int index, Duration duration)

then I need to create a wrapper thus

public IAsyncOperation<int> PlaySoundAsync(SoundGroup soundGroup, int index, Duration duration)
{
    return PlaySound(soundGroup, index, duration).AsAsyncOperation();
}

But the same trick fails with this method

public async Task PreLoadSoundPlayers()

because this

public IAsyncOperation PreLoadSoundPlayersAsync()
{
    return PreLoadSoundPlayers().AsAsyncOperation();
}

gives the error

'Task' does not contain a definition for 'AsAsyncOperation' and no extension method 'AsAsyncOperation' accepting a first argument of type 'Task' could be found

What is the correct pattern for exposing asynchronous methods that do not have a data return type in a UWP class library?

Upvotes: 1

Views: 679

Answers (1)

dumbledad
dumbledad

Reputation: 17527

Found it - I needed to use actions instead of operations.

public IAsyncAction PreLoadSoundPlayersAsync()
{
    return PreLoadSoundPlayers().AsAsyncAction();
}

Upvotes: 2

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