Question

• I am having trouble setting a bool to a method that returns a bool.
• I am using a Queue of type Task and am passing the method to the Queue as a new Task.
• How do I set a bool based off of the method call that is used inside of Task.Start() ?

• How do I re-execute a Task, so that I may call Task.Start() multiple times?

  public static void Main(string[] args)
  {
      Console.WriteLine("Performing Queue<Task> q = new Queue<Task>();");
      Queue<Task> q = new Queue<Task>();
      Console.WriteLine("Finished Queue<Task> q = new Queue<Task>();");
      Console.WriteLine("Performing q.Enqueue(new Task(() => hello(\"world\") ) );");
      q.Enqueue(new Task(() => print("hello world") ) );
      Console.WriteLine("Finished q.Enqueue(new Task(() => hello(\"world\") ) );");
      Console.WriteLine("Performing Task peek = q.Peek();");
      Task peek = q.Peek();
      Console.WriteLine("Finished Task peek = q.Peek();");
      Console.WriteLine("Performing peek.Start();");
      //bool temp = peek.Start(); // does not set temp to true, how do I accomplish this?
      peek.Start(); // Works, but does not return true as print() should return true, how do I accomplish this?
      Console.WriteLine("Finished peek.Start();");
      Console.WriteLine("Performing Task dequeue = q.Dequeue();");
      Task dequeue = q.Dequeue();
      Console.WriteLine("Finished Task dequeue = q.Dequeue();");
      Console.WriteLine("Performing dequeue.Start();");
      //bool temp2 = dequeue.Start(); // does not set temp2 to true, how do I accomplish this?
      dequeue.Start(); // How do I make a Task reexecute?
      Console.WriteLine("Finished dequeue.Start();");
  
  }
  public static bool print(string text)
  {
      Console.WriteLine("print(" +text +")");
      return true;
  }
  

Answer 1

Here is an example of how to get a return value from a Task:

http://msdn.microsoft.com/en-us/library/dd537613

The MSDN article for Task (http://msdn.microsoft.com/en-us/library/dd270682.aspx) says that:

A task may only be started and run only once. Any attempts to schedule
a task a second time will result in an exception.

I would recommend finding a way to rewrite your code using Task.Factory.StartNew() instead of new Task().Start. Here is a good article on the difference:

http://blogs.msdn.com/b/pfxteam/archive/2010/06/13/10024153.aspx

Why not queue up enum values instead of the Tasks themselves, and then write a small function to run a task based on the enum value. It could look something like:

public static void StartTask(Actions action)
{
    if (action == Actions.Print)
    {
        Task t = new Task(() => print("hello world"));
        t.Start();
    }
}

Incorporate the return values based on the first example and then you’re all set.