ConcurrentBag<T> Class

Bags are useful for storing objects when ordering doesn't matter, and unlike sets, bags support duplicates. ConcurrentBag<T> is a thread-safe bag implementation, optimized for scenarios where the same thread will be both producing and consuming data stored in the bag.

ConcurrentBag<T> accepts null as a valid value for reference types.

For more information, see the entry FAQ: Are all of the new concurrent collections lock-free? in the Parallel Programming with .NET blog.

Note

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: Synchronization | ExternalThreading. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

The following example shows how to add and remove items from a ConcurrentBag<T>:

using System;
using System.Collections.Concurrent;

class ConcurrentBagDemo
{
    // Demonstrates: 
    //      ConcurrentBag<T>.Add() 
    //      ConcurrentBag<T>.IsEmpty 
    //      ConcurrentBag<T>.TryTake() 
    //      ConcurrentBag<T>.TryPeek() 
    static void Main()
    {
        // Construct and populate the ConcurrentBag
        ConcurrentBag<int> cb = new ConcurrentBag<int>();
        cb.Add(1);
        cb.Add(2);
        cb.Add(3);

        // Consume the items in the bag 
        int item;
        while (!cb.IsEmpty)
        {
            if (cb.TryTake(out item))
                Console.WriteLine(item);
            else
                Console.WriteLine("TryTake failed for non-empty bag");
        }

        // Bag should be empty at this point 
        if (cb.TryPeek(out item))
            Console.WriteLine("TryPeek succeeded for empty bag!");
    }

}

.NET Framework

.NET Framework Client Profile

Portable Class Library

.NET for Windows Store apps

Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

All public and protected members of ConcurrentBag<T> are thread-safe and may be used concurrently from multiple threads.

Reference

Other Resources