ObservableConcurrentQueue

Using System.Collections.Concurrent.ConcurrentQueue with notifications

Get the latest version of source code from Github

Or get it from NUGET:

PM> Install-Package ObservableConcurrentQueue

Documentation

if you are not familiar with ConcurrentQueue, Read more about it on MSDN

Usage

Syntax

Create new instance

var observableConcurrentQueue = new ObservableConcurrentQueue();

Note about Thread Safety:

According to Mircosoft Documentation All public and protected members of ConcurrentQueue<T> are thread-safe and may be used concurrently from multiple threads. This additional Thread Safe option is just for some customization stuff.

Subscribe the Handler to the event ContentChanged

observableConcurrentQueue.ContentChanged += OnObservableConcurrentQueueContentChanged;

Option 2: Subscribe to CollectionChanged Event

observableConcurrentQueue.CollectionChanged += OnObservableConcurrentQueueCollectionChanged;

Example of handling method:

Queue Content Changed

private static void OnObservableConcurrentQueueContentChanged(
 object sender,
 NotifyConcurrentQueueChangedEventArgs args)
 {
      // Item Added
      if (args.Action == NotifyConcurrentQueueChangedAction.Enqueue)
      {
          Console.WriteLine("New Item added: {0}", args.ChangedItem);
      }
 
      // Item deleted
      if (args.Action == NotifyConcurrentQueueChangedAction.Dequeue)
      {
          Console.WriteLine("New Item deleted: {0}", args.ChangedItem);
      }
 
      // Item peeked
      if (args.Action == NotifyConcurrentQueueChangedAction.Peek)
      {
           Console.WriteLine("Item peeked: {0}", args.ChangedItem);
      }
 
      // Queue Empty
      if (args.Action == NotifyConcurrentQueueChangedAction.Empty)
      {
           Console.WriteLine("Queue is empty");
      }
 } 

Collection Changed event

private static void OnObservableConcurrentQueueCollectionChanged(
     object sender,
     NotifyCollectionChangedEventArgs args)
{
     if (args.Action == NotifyCollectionChangedAction.Add)
     {
          Console.WriteLine($"[+] Collection Changed [Add]: New Item added: {args.NewItems[0]}");
     }

     if (args.Action == NotifyCollectionChangedAction.Remove)
     {
          Console.WriteLine($"[-] Collection Changed [Remove]: New Item deleted: {args.OldItems[0]}");
     }

     if (args.Action == NotifyCollectionChangedAction.Reset)
     {
          Console.WriteLine("[ ] Collection Changed [Reset]: Queue is empty");
     }
}

Once the handler is defined, we can start adding, deleting or getting elements from the concurrentQueue, and after each operation an event will be raised and handled by the method above.

Event Args

The EventArgs object sent by the event contains 2 properties:

NotifyConcurrentQueueChangedAction Action:

• Enqueue: If a new item has been enqueued.
• Dequeue: an item has been dequeued.
• Peek: an item has been peeked.
• Empty: The last element in the queue has been dequeued and the queue is empty.

T ChangedItem:

The item which the changes applied on. can be null if the notification action is NotifyConcurrentQueueChangedAction.Empty.

Supported Frameworks

.NET Standard

netstandard1.1 netstandard1.2 netstandard1.3 netstandard1.4 netstandard1.5 netstandard1.6 netstandard2.0 netstandard2.1

.NET

net5.0 net6.0

.NET Core

netcoreapp1.0 netcoreapp1.1 netcoreapp2.0 netcoreapp2.1 netcoreapp2.2 netcoreapp3.0 netcoreapp3.1

.NET Framework

net40 net45 net451 net452 net46 net461 net462 net47 net471 net472 net48