C# endless list is filled and taken - BlockingCollection

Question

Hello,
I have a thread that receives data and buffers it in a list. Another thread that takes this data.

Task t1 = Task.Run(() =>  
                {  
                    bc.Add(1);  
                    bc.Add(2);  
                    bc.Add(3);  
                    bc.Add(4);  
                    bc.CompleteAdding();  
                });  
  

This is endless, I don't know when it will be completed. I can't call bc.CompleteAdding();

I am looking for a good example to solve this requirement. Can you please help me with an example? Thank you in advance.

the block diagram

Answer 1

Your scenario like ConcerentQueue without bounding. So you don't need to use CompleteAdding:

// Initialize Q and Cancelleation Token
var q = new BlockingCollection<int>();
var cts = new CancellationTokenSource();
var ct = cts.Token;

// Producer Thread.
var t1 = Task.Run(() =>
{
    int i = 0;
    do
    {
        q.Add(++i);
        Console.WriteLine(i + " is added to q");
    }
    while (!ct.IsCancellationRequested);
    Console.WriteLine("producer task is canceled");
}, ct);

// Consumer Thread.
var t2 = Task.Run(() =>
{
    do
    {
        while(q.Count > 0)
        {
            var result = q.Take();
            Console.WriteLine(result + " is removed from q");
        }
    }
    while (!ct.IsCancellationRequested);
    Console.WriteLine("consumer task is canceled");
}, ct);

To see in action, create a console app and copy the above code in the main function:

using System;
using System.Threading;
using System.Collections.Concurrent;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            // Copy above code here

            Console.Title = "Press any key to exit";
            Console.ReadLine();

            Console.Title = "Wait to Queue get empty";

            // Cancel t1 & t2
            cts.Cancel();

            // Wait for both thread to done
            Task.WaitAll(t1, t2);
        }
    }
}

See this example for using CompleteAdding.