Await for list of Tasks

Question

I'm trying to do something like this:

foreach (var o in ObjectList)  {      CalculateIfNeedToMakeTaskForO(o);      if (yes)          TaskList.Add(OTaskAsync()); } 

Now I would like to wait for all these tasks to complete. Besides doing

foreach(var o in ObjectList) {     Result.Add("result for O is: "+await OTaskAsync()); } 

Is there anything I could do? (better, more elegant, more "correct")

Answer 1

You are looking for Task.WhenAll:

var tasks = ObjectList     .Where(o => CalculateIfNeedToMakeTaskForO(o))     .Select(o => OTaskAsync(o))     .ToArray(); var results = await Task.WhenAll(tasks); var combinedResults = results.Select(r => "result for O is: " + r);