c# - BlockingCollection 是线程安全的吗？

Question

BlockingCollection<int> blockingCollection = new BlockingCollection<int>();
    // create and start a producer
    Task.Factory.StartNew(() => {
        // put items into the collectioon
        for (int i = 0; i < 1000; i++)
        {
            blockingCollection.Add(i);
        }
        // mark the collection as complete
        blockingCollection.CompleteAdding();
    });
    // create and start a producer
    Task.Factory.StartNew(() => {
        while (!blockingCollection.IsCompleted)
        {
            // take an item from the collection
            int item = blockingCollection.Take();
            // print out the item
            Console.WriteLine("Taskid{1} Item {0}", item, Task.CurrentId);
        }
    });

    // create and start a producer
    Task.Factory.StartNew(() => {
        while (!blockingCollection.IsCompleted)   // if the blockingCollection is not completed
        {
            // take an item from the collection
            int item = blockingCollection.Take();  // but in here, all the items have been taken by other thread, this line will wait forever?
            // print out the item
            Console.WriteLine("Taskid{1} Item {0}", item,Task.CurrentId);
        }
    });
    Console.ReadLine();

关键代码行:

    while (!blockingCollection.IsCompleted)   // if the blockingCollection is not completed
    int item = blockingCollection.Take();  // but in here, all the items have been taken by other thread, this line will wait forever?

Answer 1

是的，BlockingCollection<T>是线程安全的。

为了避免IsCompleted检查您是否可以在 GetConsumingEnumerable() 的帮助下放置相同的逻辑它将等到阻止收集完成:

  // Producer:

  Task.Run(() => { 
    for (int i = 0; i < 1000; i++)
      blockingCollection.Add(i);

    blockingCollection.CompleteAdding();
  });    

  // Consumers:

  Task.Run(() => {
    foreach (var item in blockingCollection.GetConsumingEnumerable()) 
      Console.WriteLine("Taskid{1} Item {0}", item, Task.CurrentId);
  });

  Task.Run(() => {
    foreach (var item in blockingCollection.GetConsumingEnumerable()) 
      Console.WriteLine("Taskid{1} Item {0}", item, Task.CurrentId);
  });