1. Start off by creating a new method called CancelParallelForEach() in the Demo class, which takes two parameters. One is a collection of List<string>, while the other is an integer specifying a timeout value. When the timeout value is exceeded, the Parallel.ForEach loop must terminate:

        public class Demo 
        { 
          public void CancelParallelForEach(List<string> intCollection, 
            int timeOut) 
          {         
   
          }     
        }

2. Inside the CancelParallelForEach() method, add a timer to keep track of the elapsed time. This will signal the loop that the timeout threshold has been exceeded and that the loop needs to exit. Create a Parallel.ForEach method defining a state. In each iteration, check the elapsed time against the timeout, and if the time is exceeded, break out of the loop:

        var timer = Stopwatch.StartNew(); 
        Parallel.ForEach(intCollection, (integer, state) => 
        { 
          Thread.Sleep(1000); 
          if (timer.Elapsed.Seconds > timeOut) 
          { 
            WriteLine($"Terminate thread {Thread.CurrentThread
              .ManagedThreadId}. Elapsed time {
              timer.Elapsed.Seconds} seconds"); 
            state.Break(); 
          } 
          WriteLine($"Processing item {integer} on thread           {Thread.CurrentThread.ManagedThreadId}"); 
        });

3. In the console application, create the List<string> object and add 1000 items to it. Call the CancelParallelForEach() method with a timeout of only 5 seconds:

        List<string> integerList = new List<string>(); 
        for (int i = 0; i <= 1000; i++) 
        { 
          integerList.Add(i.ToString()); 
        } 

        Demo oRecipe = new Demo(); 
        oRecipe.CancelParallelForEach(integerList, 5); 
        WriteLine($"Parallel.ForEach loop terminated"); 
        ReadLine();

4. Run your console application and review the output results: