Question

I have three tasks A, B, C.

B must run before C, but A can run in parallel to both of them. This is logic that has recently changed, and the logic we currently have works fine, I just wondered if there is a better solution to what we currently have:

public void RunTasks(...) {
    Action<IRunnableTask> runner = task => 
    {
        if (task.ShouldRun(request))
        {
            task.Run(request, response);
        }
    };

    // run parallel tasks
    Parallel.ForEach(parallelTasks, runner);

    // run serial tasks
    Array.ForEach(serialTasks, runner);
}

Here, A and B would be parallel tasks, C is in the list of serial tasks. The problem is here that the code will wait for A to finish before C can start, which is unnecessary.

So, is there a nice clean solution, or do I need to start putting in callbacks and whatnot?

Answer 1

You could make use of Tasks from the TPL.

You could run Tasks B and A at the same time, then have task C run as a continuation of Task B

e.g.

Task.Factory.StartNew(()=>TaskA());
Task.Factory.StartNew(()=>TaskB()).ContinueWith(t=>TaskC(t));

In the continuation of TaskB, you can pass in the Task to get any result of TaskB passed into the TaskC method.