private static Task <TResult> ExecuteAsync <TResult>(SpreadsheetsService service, object userData, IAggregateProgress progress, CancellationToken cancellationToken, Func <AsyncOperationCompletedEventArgs, TResult> getResult)
where TResult : AtomBase
{
var taskSource = new TaskCompletionSource <TResult>();
AsyncOperationProgressEventHandler progressHandler = null;
if (progress != null)
{
progressHandler = (sender, eventArgs) =>
{
if (eventArgs.UserState == userData)
{
progress.Report(eventArgs.ProgressPercentage);
}
};
service.AsyncOperationProgress += progressHandler;
}
AsyncOperationCompletedEventHandler evnetHandler = null;
evnetHandler = (sender, eventArgs) =>
{
if (eventArgs.UserState == userData)
{
service.AsyncOperationCompleted -= evnetHandler;
if (progress != null)
{
progress.Report(100);
service.AsyncOperationProgress -= progressHandler;
}
if (eventArgs.Error != null)
{
taskSource.TrySetException(eventArgs.Error);
}
else
{
taskSource.TrySetResult(getResult(eventArgs));
}
}
};
service.AsyncOperationCompleted += evnetHandler;
cancellationToken.Register(() =>
{
if (taskSource.TrySetCanceled())
{
service.AsyncOperationCompleted -= evnetHandler;
if (progress != null)
{
service.AsyncOperationProgress -= progressHandler;
}
service.CancelAsync(userData);
}
});
return(taskSource.Task);
}