Ensuring primary thread waits for all Tasks to complete

Question

I\'m writing a C# console app and having an issue where the primary thread closes before all the spawned off Tasks have a chance to complete. General program flow looks like thi

Answer 1

You can put all of the tasks you get into a List<Task> instead of just creating them and tossing them, and then use the Task.WaitAll() to wait for completion:

var tasks = new List<Task>();

foreach (KeyValuePair<string, List<string>> entry in productDictionary) {
    string writePath = String.Format(@"{0}\{1}-{2}.txt", directoryPath, hour, entry.Key);
    List<string> quotes = entry.Value;

    // add task to list
    tasks.Add(Task.Factory.StartNew(() => WriteProductFile(writePath, quotes)));
}

// now wait for all tasks to finish, you'd also want to handle  exceptions of course.
Task.WaitAll(tasks.ToArray());

There are many variations of WaitAll(), you could wait indefinitely (as above), or wait for a TimeSpan and if time-out then print a progress message and wait again, etc...