The “FromAsync” method in the Task Framework helps to build
Task object from the “Async” methods (APM). Below code is an example of the
same.
Also beside, using “FromAsync”
method, “TaskCompletionSource” object helps to set the result in the callback
method.
Below code has both as examples.
namespace ConsoleApplication5
{
class Program
{
delegate int delSum(int a, int b);
static void Main(string[] args)
{
try
{
delSum oSum = new delSum((a1, a2) =>
{
Thread.Sleep(2000);
return a1 + a2;
});
//Using "From Async" method to
convert APM to TAP
Task<int>
aa = Task<int>.Factory.FromAsync(
oSum.BeginInvoke, oSum.EndInvoke, 4, 5, null);
aa.ContinueWith(t => Console.WriteLine("using from async method " + t.Result));
//Using "Task Completion Source", to
set the task result from IAsyncResult
TaskCompletionSource<int> source = new TaskCompletionSource<int>();
oSum.BeginInvoke(8, 9, ar =>
{
try
{
source.SetResult(oSum.EndInvoke(ar));
}
catch (Exception
exp)
{
Console.WriteLine("Error
: " + exp.Message);
}
}, null);
source.Task.ContinueWith(t => Console.WriteLine("using task completion source " +
t.Result));
}
catch (Exception
exp)
{
Console.WriteLine("Error : " + exp.Message);
}
Console.Read();
}
}
}
