What is the difference between task and thread?

Question

In C# 4.0, we have Task in the System.Threading.Tasks namespace. What is the true difference between Thread and Task. I did s

Answer 1

A Task can be seen as a convenient and easy way to execute something asynchronously and in parallel.

Normally a Task is all you need, I cannot remember if I have ever used a thread for something else than experimentation.

You can accomplish the same with a thread (with lots of effort) as you can with a task.

Thread

int result = 0;
Thread thread = new System.Threading.Thread(() => { 
    result = 1; 
});
thread.Start();
thread.Join();
Console.WriteLine(result); //is 1

Task

int result = await Task.Run(() => {
    return 1; 
});
Console.WriteLine(result); //is 1

A task will by default use the Threadpool, which saves resources as creating threads can be expensive. You can see a Task as a higher level abstraction upon threads.

As this article points out, task provides following powerful features over thread.

• Tasks are tuned for leveraging multicores processors.

• If system has multiple tasks then it make use of the CLR thread pool internally, and so do not have the overhead associated with creating a dedicated thread using the Thread. Also reduce the context switching time among multiple threads.

• Task can return a result.There is no direct mechanism to return the result from thread.

• Wait on a set of tasks, without a signaling construct.

• We can chain tasks together to execute one after the other.

• Establish a parent/child relationship when one task is started from another task.

• Child task exception can propagate to parent task.

• Task support cancellation through the use of cancellation tokens.

• Asynchronous implementation is easy in task, using’ async’ and ‘await’ keywords.