How to run tasks in parallel and select the first result that satisfies a given condition in C #?

Question

There are three tasks that I want to run in parallel. I want to study the result of the first completed task and check to decide if the result is good. If yes, I cancel all other tasks and return this result, if not, I will wait for the next completed task and check if this is good and what to do, if so. (Think of being good, like some simple member check of OutputDataType).

I continue this until I get a completed task with a good result, or all tasks return with results that are not good, in which case I return null.

Thanks in advance.

using System;
using System.Threading;
using System.Threading.Tasks;
namespace myNamespace
{
    class Program
    {
        static void Main()
        {
            InputDataType data = getMyData();
            OutputDataType x = Foo(data);
        }   

        static OutputDataType Foo(InputDataType data)
        {
            Task<OutputDataType> task1 = null, task2 = null, taks3 = null;
            Task<OutPutDataType>[] TaskArray = { task1, task2, task3 };

            task1 = Task<SolutionInterpreters>.Factory.StartNew(() => RunFunc1(data));
            task2 = Task<SolutionInterpreters>.Factory.StartNew(() => RunFunc2(data));
            task3 = Task<SolutionInterpreters>.Factory.StartNew(() => RunFunc3(data));

            /*
            .
            .
            .
            */
        }
    }
}

Answer 1

TPL , , . - CancellationTokenSource, RunFuncX.

static void Main()
{
    InputDataType data = getMyData();
    OutputDataType x = Foo(data).Result;
}   

static async Task<OutputDataType> Foo(InputDataType data)
{
    // Spawn your tasks, passing the cancellation token.
    var cts = new CancellationTokenSource();
    var task1 = Task.Factory.StartNew(() => RunFunc1(data, cts.Token));
    var task2 = Task.Factory.StartNew(() => RunFunc2(data, cts.Token));
    var task3 = Task.Factory.StartNew(() => RunFunc3(data, cts.Token));
    var tasks = new [] { task1, task2, task3 };

    // Loop while tasks are running.
    while (tasks.Any())
    {
        // Wait for any task to complete.
        var completedTask = await Task.WhenAny(tasks);

        // If its result is good, indicate cancellation to the other tasks,
        // and return the result.
        if (IsResultGood(completedTask.Result))
        {
            cts.Cancel();
            return completedTask.Result;
        }

        // Otherwise, remove the completed task from the array,
        // and proceed to the next iteration.
        tasks = tasks.Where(t => t != completedTask).ToArray();
    }

    // No good results.
    return null;
}

Spo1ler Foo . , # 5.0. await, . , , Result.