How to Invoke the Thread in a for loop

Question

Hi I want to pass sleeptime and the Thread Object to a method and call the method in a for loop. Pls see the code below

public delegate void PasParamsToThrdFunc(int integer, object obj2);
class Program
{
    Thread[] newThread=new Thread[10];

    static void Main(string[] args)
    {
        Program pr = new Program();
        pr.ThreadDeclaration();
        Console.Read();
    }

    public void ThreadDeclaration()
    {
        int time = 5000;
        for(int i=1;i<3;i++)
        {
            time = time * i;
            string s = i.ToString();
            ThreadStart starter = () => PasParamsToThrdFunc(time, newThread[i]);
            newThread[i] = new Thread(starter);
            newThread[i].Name = i.ToString();
            newThread[i].Start();
        }

    }

    public void PasParamsToThrdFunc(int waitTime, Thread obj)
    {
        Thread.Sleep(waitTime);
        Console.WriteLine("" + waitTime + " seconds completed and method is called for thread"+obj.Name+"");
        obj.Abort();
    }
  }

I want the 1st thread to be invoked after 5 seconds and shall kill the object and shall do the same for the 2nd thread and kill it at 10 seconds. Please help... Thanks in advance.

Seems more reasonable to use a [`System.Timers.Timer`](http://msdn.microsoft.com/en-us/library/system.timers.timer.aspx). — Albin Sunnanbo, Nov 12 '12 at 13:39
Anand Patel... There will always be a technology which is new.. This is new to me.. So dont think its a school assignment. — user1606651, Nov 16 '12 at 13:20

score 0 · Answer 1 · edited May 23 '17 at 12:04

1- when you pass newThread[i] to PasParamsToThrdFunc it is null. Change it to i

2- You may need to avoid closing over variables i and time

public void ThreadDeclaration()
{
    int time = 5000;
    for (int i = 1; i < 3; i++)
    {
        int J = i; // <----
        int timez = time * i; // <----
        string s = i.ToString();

        ThreadStart starter = () => PasParamsToThrdFunc(timez, J);
        newThread[i] = new Thread(starter);
        newThread[i].Name = i.ToString();
        newThread[i].Start(); 
    }

}

public void PasParamsToThrdFunc(int waitTime, int i )
{
    Thread.Sleep(waitTime);
    Console.WriteLine("" + waitTime + " seconds completed and method is called for thread" + newThread[i].Name + "");
    newThread[i].Abort(); // <-- No need
}

Matthew Watson · Answer 2 · 2012-11-12T13:58:27.427

There are a few problems I can see:

You are accessing modified closures with the parameters you are passing to the thread function (you shouldn't modify those params after passing them).
You passing a thread's handle to itself and then using it to abort itself. No need to do that, since it will just exit when after the sleep.
You are calculating time incorrectly, by multiplying itself by i on each iteration, rather than using the time interval * i.

Try something like this instead:

using System;
using System.Threading;

namespace Demo
{
    class Program
    {
        static void Main(string[] args)
        {
            Program pr = new Program();
            pr.ThreadDeclaration();
            Console.Read();
        }

        public void ThreadDeclaration()
        {
            int timeInterval = 5000;

            for (int i=1; i<3; i++)
            {
                int time = timeInterval * i;
                ThreadStart starter = () => PasParamsToThrdFunc(time);
                var thread = new Thread(starter) {Name = i.ToString()};
                thread.Start();
            }
        }

        public void PasParamsToThrdFunc(int waitTime)
        {
            Thread.Sleep(waitTime);
            Console.WriteLine("" + waitTime + " seconds completed and method is called for thread" + Thread.CurrentThread.Name);

        }
    }
}

How to Invoke the Thread in a for loop

2 Answers2