BlockingCollection<T> 类 粗略学习经验

BlockingCollection 类 实现 IProducerConsumerCollection 的线程安全集合提供阻塞和限制功能。

我的理解是 生产者向集合内按照队列的形式添加元素，读取按照队列的方式读取，当集合中没有了元素，读取就会阻塞线程（GetConsumingEnumerable()）

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

namespace BlockingCollectionDemo
{
    class Program
    {
        static void Main(string[] args)
        {

            Parallel.Invoke(Test.AddItem, Test.Read, Test.IsCompleted);


            Console.WriteLine("Hello World!");
        }
    }

    public class Test
    {
        private readonly static BlockingCollection<int> cols = new BlockingCollection<int>();

        public static void AddItem()
        {
            for (var i = 0; i < 10; i++)
            {
                cols.Add(i);
                Console.WriteLine("write value:{0}", i);
                Thread.Sleep(1000);
            }
            cols.CompleteAdding(); // 不执行该方法，会造成 GetConsumingEnumerable() 阻塞
            var iscompleted = cols.IsAddingCompleted;
            Console.WriteLine("add completed value:{0}", iscompleted);
            var isscompleted = cols.IsCompleted;
            Console.WriteLine("a completed value:{0}", isscompleted);
        }

        public static void Read()
        {
            foreach (var item in cols.GetConsumingEnumerable())
            {
                var iscompleted = cols.IsCompleted;
                Console.WriteLine("b completed value:{0}", iscompleted);
                Console.WriteLine("read value:{0}", item);
                Thread.Sleep(1500);
            }
            Console.WriteLine("read done.");
        }

        public static void IsCompleted()
        {
            var iscompleted = false;
            while (!iscompleted)
            {
                iscompleted = cols.IsCompleted;
                Console.WriteLine("completed value:{0}", iscompleted);
                Thread.Sleep(1000);
            }
        }

    }
}

TryTake 不会阻塞 ，但是 如果队列中没有元素，将获取元素默认值

详细文档请看文档 https://docs.microsoft.com/zh-cn/dotnet/api/system.collections.concurrent.blockingcollection-1?view=net-5.0