Starting tasks
Learn to start tasks with Task.Run and Task.Factory.StartNew.
Ways to start a Task
In C# you start a Task in a few ways: call an async method and await it (cleanest), offload CPU work with Task.Run, or build a ready-result Task with Task.FromResult.
Older code used new Task(...) followed by .Start(); this is no longer recommended. The Thread class is lower level and is not used in place of async/await. For new code, embrace async method + await.
Task.Run vs new Task
Task.Run immediately sends work to the pool and returns a Task. new Task(...) creates the Task but does not start it; you must also call .Start(). This extra step is error-prone.
So new code prefers Task.Run. For CPU work use the await Task.Run(() => Work()) pattern. For I/O call an async method directly; do not waste a pool thread.
Exercise Start work with Task.Run
Define static string BuildMessage() (return "Ready";). Make Main a static async Task Main. Produce the message in the pool with string msg = await Task.Run(() => BuildMessage()); and print with Console.WriteLine(msg);.
Show example solution
In BuildMessage body write return "Ready";. Make Main static async Task Main() and write string msg = await Task.Run(() => BuildMessage()); Console.WriteLine(msg);
Example solution:
using System;
using System.Threading.Tasks;
class Program
{
static string BuildMessage()
{
return "Ready";
}
static async Task Main()
{
string msg = await Task.Run(() => BuildMessage());
Console.WriteLine(msg);
}
}Test yourself
-
What is the recommended way to start a Task?
- new Task(() => {})
- async method call + await
- Thread.Start
- ThreadPool.QueueUserWorkItem
Show answer
async method call + await — Correct. An async method call + await is the cleanest way to start.
-
Complete the Task.Run call
Task t = Task.____(() => Work());Show answer
Task t = Task.Run(() => Work()); -
What does Task.Run return?
- void
- Thread
- Task
- IEnumerable
Show answer
Task — Correct. Task.Run returns a Task; you await it.