Transform IEnumerable<Task<T>> asynchronously by awaiting each task

Question

Today I was wondering how to transform a list of Tasks by awaiting each of it. Consider the following example:

private static void Main(string[] args) {     try     {         Run(args);                         Console.ReadLine();     }     catch (Exception ex)     {         Console.WriteLine(ex.ToString());         Console.ReadLine();     } }  static async Task Run(string[] args) {     //Version 1: does compile, but ugly and List<T> overhead     var tasks1 = GetTasks();                             List<string> gainStrings1 = new List<string>();     foreach (Task<string> task in tasks1)     {         gainStrings1.Add(await task);     }     Console.WriteLine(string.Join("", gainStrings1));      //Version 2: does not compile     var tasks2 = GetTasks();     IEnumerable<string> gainStrings2 = tasks2.Select(async t => await t);     Console.WriteLine(string.Join("", gainStrings2)); }  static IEnumerable<Task<string>> GetTasks() {     string[] messages = new[] { "Hello", " ", "async", " ", "World" };      for (int i = 0; i < messages.Length; i++)     {         TaskCompletionSource<string> tcs = new TaskCompletionSource<string>();         tcs.SetResult(messages[i]);         yield return tcs.Task;     } } 

I'd like to transform my list of Tasks without the foreach, however either the anonymous function syntax nor the usual function syntax allows me to do what my foreach does.

Do I have to rely on my foreach and the List<T> or is there any way to get it to work with IEnumerable<T> and all its advantages?

Answer 1

What about this:

await Task.WhenAll(tasks1); var gainStrings = tasks1.Select(t => t.Result).ToList(); 

Wait for all tasks to end and then extract results. This is ideal if you don't care in which order they are finished.

EDIT2: Even better way:

var gainStrings = await Task.WhenAll(tasks1);