Task.WaitAll () is not working properly

Question

I am trying to figure out how to work with the Task class. In the past, I have always used the regular Thread class, but I'm trying to understand all asynchronous programming ...

As an example, I created the main Winforms application, which has all the code. Relevant code for my problem:

//Relevant delegates
public delegate void MethodAction(int num);
public delegate void MethodConversion();
public delegate void OnCompletionAction(string completiontext);

//Button user presses
private void button4_Click(object sender, EventArgs e)
{
    richTextBox1.Clear();
    sw.Reset();
    sw.Start();
    Sync.RunAsync3(calcSim);
}

//The method that simulates a calculation by adding a sleep
//the input param threadlength is just to allow threads to take longer than others
//since I'm multithreading, I have to invoke the writing code on the windows RichTextbox control
private void calcSim(int threadlength)
{
    string threadname = Thread.CurrentThread.Name;
    for (int i = 0; i < 10; i++) //Thread calc should take 3s
    {
        Thread.Sleep(300 + threadlength);
        richTextBox1.Invoke((MethodConversion)(() =>
                            { 
                                richTextBox1.AppendText(string.Format("Thread: {0}\tVersion: {1}\n", threadname, (i + 1).ToString())); 
                            }));
    }
}

//Class that contains the different processing methods
public static class Sync
{
    public static event OnCompletionAction OnProcCompletion;

    public static void RunAsync3(MethodAction doM)
    {
        Task[] t = new Task[4];
        for(int i = 0; i < 4; i++)
        {
            t[i] = Task.Factory.StartNew((Action)(() => { doM(50 * i); }));
        }
        Task.WaitAll(t);
        if (OnProcCompletion != null) OnProcCompletion("RunSync method finished");
    }
}

The problem is Task.WaitAll (t) ... For some reason that I cannot understand, it completely blocks this line and no longer responds. If I omit this line, the form is updated in real time, and the execution takes about 3 seconds.

My question is: why doesn't Task.WaitAll () block the UI thread for 3 seconds before releasing it and allowing the rest of the code to execute?

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WhenAll WaitAll. RunAsync3 :

public static void RunAsync3(MethodAction doM)
{
    Task[] t = new Task[4];
    for(int i = 0; i < 4; i++)
    {
        t[i] = Task.Factory.StartNew((Action)(() => { doM(50 * i); }));
    }
    //Task.WaitAll(t); -> deadlock
    Task.WaitAll(new Task [] { Task.WhenAll(t) });
    if (OnProcCompletion != null) OnProcCompletion("RunSync method finished");
}

...? , WhenAll?

2

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private void button4_Click(object sender, EventArgs e)
{
    Thread t = new Thread(new ThreadStart(() =>
    {
        richTextBox1.Invoke((MethodConversion)(() => richTextBox1.Clear()));
        sw.Reset();
        sw.Start();
        Sync.RunAsync3(calcSim);
    }));
    t.Start();
}
public static void RunAsync3(MethodAction doM)
{
    Task[] t = new Task[4];
    for(int i = 0; i < 4; i++)
    {
        t[i] = Task.Factory.StartNew((Action)(() => { doM(50 * i); }));
    }
    Task.WaitAll(t);
   //Task.WaitAll(new Task [] { Task.WhenAll(t) });
   if (OnProcCompletion != null) OnProcCompletion("RunSync method finished");
}

Answer 1

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4 .

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Task.WhenAll(). , , . , , calcSim , .

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await Task.WhenAll(t);

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await , - 4 . , RunAsync3 .

Answer 2

Task.WaitAll , .

richTextBox1.Invoke ( ), Task.WaitAll. .

Answer 3

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