Map async result with automapper

Question

We are createing a Web.Api application of a angularjs application. The Web.Api returns a json result.

Step one was getting the data:

    public List

        

Answer 1

Jose's solution proved quite useful to me. I did, however, re-target the extension method to extend IMapper which allowed me to remove the singleton Mapper reference.

public static class MapperExtensions
{
    public static Task MapAsync(this IMapper mapper, Task task)
    {
        if (task == null)
        {
            throw new ArgumentNullException(nameof(task));
        }

        var tcs = new TaskCompletionSource();

        task
            .ContinueWith(t => tcs.TrySetCanceled(), TaskContinuationOptions.OnlyOnCanceled);

        task
            .ContinueWith
            (
                t =>
                {
                    tcs.TrySetResult(mapper.Map(t.Result));
                },
                TaskContinuationOptions.OnlyOnRanToCompletion
            );

        task
            .ContinueWith
            (
                t => tcs.TrySetException(t.Exception),
                TaskContinuationOptions.OnlyOnFaulted
            );

        return tcs.Task;
    }
}