7 ways to start a Task in .NET C#

New threads can be started using the Task Programming Library in .NET in – at last – 5 different ways.

You’ll first need to add the following using statement:

using System.Threading.Tasks;

The most direct way

Task.Factory.StartNew(() => {Console.WriteLine("Hello Task library!"); });

Using Action

Task task = new Task(new Action(PrintMessage));
task.Start();

…where PrintMessage is a method:

private void PrintMessage()
{
    Console.WriteLine("Hello Task library!");
}

Using a delegate

Task task = new Task(delegate { PrintMessage(); });
task.Start();

Lambda and named method

Task task = new Task( () => PrintMessage() );
task.Start();

Lambda and anonymous method

Task task = new Task( () => { PrintMessage(); } );
task.Start();

Using Task.Run in .NET4.5

public async Task DoWork()
{
	await Task.Run(() => PrintMessage());
}

Using Task.FromResult in .NET4.5 to return a result from a Task

public async Task DoWork()
{
	int res = await Task.FromResult<int>(GetSum(4, 5));	
}

private int GetSum(int a, int b)
{
	return a + b;
}

You cannot start a task that has already completed. If you need to run the same task you’ll need to initialise it again.

View the list of posts on the Task Parallel Library here.