How to construct a Task without starting it?

G. Stoynev picture G. Stoynev · Apr 17, 2013 · Viewed 31.4k times · Source

I want to use this Task<TResult> constructor. I can't seem to get the syntax right. Could someone correct my code?

Also, am I right thinking that if a Task is constructed that way, it's not started?

The constructor I think I need is:

Task<TResult>(Func<Object, TResult>, Object)

The error I get is:

Argument 1: cannot convert from 'method group' to 'System.Func<object,int>'

static void Main(string[] args)
{
    var t = new Task<int>(GetIntAsync, "3"); // error is on this line
    // ...
}

static async Task<int> GetIntAsync(string callerThreadId)
{
    // ...
    return someInt;
}

Answer

Vyacheslav Volkov picture Vyacheslav Volkov · Apr 17, 2013
var t = new Task<int>(() => GetIntAsync("3").Result);

Or

var t = new Task<int>((ob) => GetIntAsync((string) ob).Result, "3");

To avoid using lambda, you need to write a static method like this:

private static int GetInt(object state)
{
   return GetIntAsync(((string) state)).Result;
}

And then:

var t = new Task<int>(GetInt, "3");