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How to use async/await with a library that uses an event-based asynchronous pattern?

I use a library that has an asynchronous method called DoWork(...) that will raise a WorkDone event when the operation completes.

I would like to write a method that calls this library, but instead of maintaining the same pattern I would like my method to be async so it can be called with await.

In essence, what I am trying to do is:

public async Task<Result> SomeMethod()
{
    var result = new Task<Result>();

    library.WorkDone += (data) =>
    {
        result.Result = data;
    }
    library.DoWork();

    return await result;
}

(not working because Result is readonly)

Can this be done?

like image 978
Xavier Poinas Avatar asked Dec 02 '25 10:12

Xavier Poinas


1 Answers

I will build on ws0205's answer:

First, you indicate that you want your method "to be called with await". You achieve this by returning a Task.

I also think that it's better to make the following adjustments to ws0205's answer:

public Task<Result> SomeMethod() //no async, since we're not awaiting anything
{
   var result = new TaskCompletionSource<Result>();

   library.WorkDone += (data) =>
                                {
                                    result.TrySetResult(data); //just in case 
                                };
   library.DoWork();

   return result.Task; //no need to await - we're returning a Task - let the caller await (or not)
}
like image 161
G. Stoynev Avatar answered Dec 05 '25 01:12

G. Stoynev



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