I've been trying for a while to get something I thought would be simple working with .NET 4.5
I want to fire off two long running tasks at same time and collect the
results in in the best C# 4.5 (RTM) way
The following works but I don't like it because:
Sleep
to be an async method so it can await
other methodsTask.Run()
Working code:
public static void Go()
{
Console.WriteLine("Starting");
var task1 = Task.Run(() => Sleep(5000));
var task2 = Task.Run(() => Sleep(3000));
int totalSlept = task1.Result + task2.Result;
Console.WriteLine("Slept for a total of " + totalSlept + " ms");
}
private static int Sleep(int ms)
{
Console.WriteLine("Sleeping for " + ms);
Thread.Sleep(ms);
Console.WriteLine("Sleeping for " + ms + " FINISHED");
return ms;
}
Non working code:
Update: This actually works and is the correct way to do it, the only problem is the Thread.Sleep
This code doesn't work because the call to Sleep(5000)
immediately starts the task running so Sleep(1000)
doesn't run until it has completed. This is true even though Sleep
is async
and I'm not using await
or calling .Result
too soon.
I thought maybe there is a way to get a non-running Task<T>
by calling an async
method so I could then call Start()
on the two tasks, but I can't figure out how to get a Task<T>
from calling an async method.
public static void Go()
{
Console.WriteLine("Starting");
var task1 = Sleep(5000); // blocks
var task2 = Sleep(1000);
int totalSlept = task1.Result + task2.Result;
Console.WriteLine("Slept for " + totalSlept + " ms");
}
private static async Task<int> Sleep(int ms)
{
Console.WriteLine("Sleeping for " + ms);
Thread.Sleep(ms);
return ms;
}
async Task<int> LongTask1() {
...
return 0;
}
async Task<int> LongTask2() {
...
return 1;
}
...
{
Task<int> t1 = LongTask1();
Task<int> t2 = LongTask2();
await Task.WhenAll(t1,t2);
//now we have t1.Result and t2.Result
}