Asynchronous Task

Question

Hi Friends. I am trying to run an asyncronous Task like the one below but it only executes the one line Purchasing as seen in the jpg image. It should execute the rest of the code in the Task. I also received the warning...The current method calls an async method that returns a Task or a Task<TResult> and doesn't apply the await operator to the result. The call to the async method starts an asynchronous task. However, because no await operator is applied, the program continues without waiting for the task to complete. In most cases, that behavior isn't what you expect. Usually other aspects of the calling method depend on the results of the call or, minimally, the called method is expected to complete before you return from the method that contains the call.

 public  async Task MakePurchase(PurchaseMessenger messenger, PurchaseMessenger messenger2)
        {
            Console.WriteLine("Purchasing...");
            await Task.Delay(2000);

           Console.WriteLine("Sorry for the delay...\n");
            //messenger points to NotifyPurchase()
            messenger();

            //messenger2 points to NotifyPerson()
            messenger2();
        }

AsyncIssue.JPG

Answer 1

when the caller calls MakePurchase() it returns a task when it execute the first await. if the caller of MakePurchase() does not use await, continuation routine or .Wait() then it will not know when the task completed.

var task = MakePurchase(...);
dosomething1(); // MakePurchase has not called messenger yet
dosomething2(); // unknown state
task.Wait();   // will block thread until task completed calling messenger2()