Task.Factory.StartNew(someMethod(withParam)).continueWith(sameMethod(differentParam)).Wait()

.net, c#, task-parallel-library

Solution

Do you want your `doOne` calls to occur concurrently? Then you can just start them straight from the task factory:

// Start two concurrent tasks
var task1 = Task.Factory.StartNew(() => doOne(SelectedTask.option1));
var task2 = Task.Factory.StartNew(() => doOne(SelectedTask.option2));

// Block the current thread until all tasks complete
Task.WaitAll(task1, task2);

Do you want your `doOne` calls to occur sequentially? Then you can chain them using `ContinueWith`:

// Start a chain of tasks
var task1 = Task.Factory.StartNew(() => doOne(SelectedTask.option1));
var task2 = task1.ContinueWith(t => doOne(SelectedTask.option2));

// Block the current thread until the last task completes
task2.Wait();

The code in the title of your post (with a couple of fixes) is essentially performing the exact same function as my sequential task chain above:

Task.Factory.StartNew(() => doOne(SelectedTask.option1))
            .ContinueWith(t => doOne(SelectedTask.option2))
            .Wait();

Answer to your question below.

If I understand correctly, you want to be able to run a task for a variable list of `SelectedTasks` in parallel:

List<SelectedTask> selectedTaskOptions = new List<SelectedTask>()
{
    SelectedTask.option1,
    SelectedTask.option2,
    SelectedTask.option3,
    SelectedTask.option4,
    SelectedTask.option5
};

RunAllSelectedTaskOptions(selectedTaskOptions);

`RunAllSelectedTaskOptions` to accept and run a list of `SelectedTasks`:

public void RunAllSelectedTaskOptions(List<SelectedTask> selectedTaskOptions)
{
    List<Task> createdTasks = new List<Task>();

    foreach(var taskOption in selectedTaskOptions)
    {
        createdTasks.Add(Task.Factory.CreateNew(() => doOne(taskOption)));
    }

    Task.WaitAll(createdTasks);
}

Another way of implementing `RunAllSelectedTaskOptions` would be to use `Parallel.ForEach`, which will execute in parallel and will block until the slowest/last iteration has completed:

public void RunAllSelectedTaskOptions(List<SelectedTask> selectedTaskOptions)
{
    Parallel.ForEach(selectedTaskOptions, taskOption => doOne(taskOption));
}

Problem

What is the correct syntax for parallelizing the following code? ``` static void Main(string[] args) { Task.Factory.StartNew( () => doOne(SelectedTask.option1) .ContinueWith( task => doOne(SelectedTask.option1)).Wait() ); } ``` Same method with `enum` "selectedTask" to decide which code to execute : ``` static enum SelectedTask { option1, option2 } static void doOne(SelectedTask Lunch) { switch (lunch) { case SelectedTask.option1: Console.WriteLine("option1"); break; case SelectedTask.option2: Console.WriteLine("option2"); break; default: break; } } ```

Original source