CODEWITHSUNDEEP
c#winformstask-parallel-library
faizanjehangir
faizanjehangir

Reputation: 2851

Restart all the tasks in array when completed

I have an array of subTasks, which execute a method, Once the job is completed I get a notification and its over. Now I want them to restart the same job again, without any hassle. How is this possible?

This is how I am creating the task array and working with task completion:

public void Start()
        {

            this.totalRangePerThread = ((this.endRange - this.startRange) / this.subTasks.Length);

            for (int i = 0; i < this.subTasks.Length; ++i)
            {
                var copy = startRange;
                this.subTasks[i] = new Task(() => searchItem(copy, this.totalRangePerThread), this.token, TaskCreationOptions.LongRunning);
                this.startRange = this.startRange + this.totalRangePerThread;
            }

            //start tasks
            for (int taskIndex = 0; taskIndex < this.subTasks.Length; ++taskIndex)
            {
                    this.subTasks[taskIndex].Start();     
            }
            Task.Factory.ContinueWhenAll(this.subTasks, completedTasks =>
            {
                //write it onto the the activitylog
                if (Form1.Instance != null)
                {
                    Form1.Instance.BeginInvoke((MethodInvoker)delegate
                    {
                        Form1.Instance.AddItemtoActivityLog("Search Completed!");
                    });
                }
            });

        }

Should I make another call to the Start() method or there is a mechanism that just magically restarts the subtasks?

Upvotes: 0

Views: 1914

Answers (2)

Fung
Fung

Reputation: 3558

You can extract the code for preparing and executing subtasks to a separate method. Then call it twice in your Start() method:

private void ExecuteSubTasks()
{
    var tasks = new Task[]
        {
            new Task(() => Console.WriteLine("SubTask1 executed.")),
            new Task(() => Console.WriteLine("SubTask2 executed.")),
            new Task(() => Console.WriteLine("SubTask3 executed.")),
        };

    foreach (var task in tasks)
        task.Start();
    Task.WaitAll(tasks);
}

private void Start()
{
    var mainTask = Task.Factory.StartNew(() => ExecuteSubTasks())
        .ContinueWith((prev) =>
        {
            ExecuteSubTasks();
            this.Invoke((MethodInvoker)delegate { MessageBox.Show("Completed."); });
        });
}

Upvotes: 1

David
David

Reputation: 16277

public void Start()
{
    var yourTasks = new Task[] {
    Task.Factory.StartNew(_ => task1(),
    Task.Factory.StartNew(_ => task2(),
    Task.Factory.StartNew(_ => ...
    Task.Factory.StartNew(_ => taskN() };
    Task.WaitAll(yourTasks ); // wait for all N tasks to complete
    Start();
}

Upvotes: 1

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