Question

I need to execute 3 parallel tasks and after completion of each task they should call the same function which prints out the results.

I don’t understand in .net why we have Asychronous calling (delegate.BeginInvoke() & delegate.EndInvoke()) as well as Thread class?

I’m little confused which one to use when? Now in this particular case, what should I use Asychronous calling or Thread class?

I’m using C#.

Answer 1

1. Asynchronous Delegates

Asychronous calling is used when you
have work items that should be handled
in the background and you care when
they finish.

BackgroundWorker vs background Thread

2. BackgroundWorker

• Use BackgroundWorker if you have a single task that runs in the
  background and needs to interact with
  the UI. and use it if you don’t care when they finish their task. The task of marshalling data
  and method calls to the UI thread are
  handled automatically through its
  event-based model.
• Avoid BackgroundWorker if (1) your assembly does not already
  reference the System.Windows.Form
  assembly, (2) you need the thread to
  be a foreground thread, or (3) you
  need to manipulate the thread
  priority.

3. ThreadPool

• Use a ThreadPool thread when efficiency is desired. The ThreadPool
  helps avoid the overhead associated
  with creating, starting, and stopping
  threads.
• Avoid using the ThreadPool if (1) the task runs for the lifetime of your
  application, (2) you need the thread
  to be a foreground thread, (3) you
  need to manipulate the thread
  priority, or (4) you need the thread
  to have a fixed identity (aborting,
  suspending, discovering).

4. Thread class

• Use the Thread class for long-running tasks and when you
  require features offered by a formal
  threading model, e.g., choosing
  between foreground and background
  threads, tweaking the thread priority,
  fine-grained control over thread
  execution, etc.