Summary

Represents a first-in, first-out (FIFO) collection of objects.

Remarks

A Queue is a collection that is used for FIFO (first-in, first-out) operations. Objects are enqueued (added) to the end of the Queue and dequeued (removed) from the beginning of the Queue.

The Queue class is not specific to a particular type of element. It can store any type of object. For a generic equivalent, see System.Collections.Generic.Queue<T>.

The elements in the Queue are stored in objects. This means that you can store any type of object, including null references. The type of the elements is not restricted to that of a specific type.

The Queue allows duplicate elements.

If the number of elements in the Queue exceeds the capacity, the Queue is automatically resized by reallocating memory.

The Queue is not thread-safe. If you need thread-safe access to the Queue, consider using the synchronized wrapper returned by Queue.Synchronized(Queue) method.

Public Fields ►

This class has no public fields.

Public Properties ►
Name Description
Count Gets the number of elements contained in the Queue<T>.
IsSynchronized Gets a value indicating whether access to the Queue is synchronized (thread-safe).
Public Methods ►
Name Description
Clear() Removes all elements from the Queue.
Clone() Creates a shallow copy of the Queue.
Contains(Object obj) Determines whether an element is in the Queue.
CopyTo(Array array, int index) Copies the entire Queue to a one-dimensional Array, starting at the specified index of the target array.
Dequeue() Removes and returns the object at the beginning of the Queue.
Enqueue(Object obj) Adds an object to the end of the Queue.
Equals(Object obj) Determines whether the specified object is equal to the current object.
GetEnumerator() Returns an enumerator that iterates through the Queue.
GetHashCode() Serves as the default hash function.
GetType() Gets the Type of the current instance.
Peek() Returns the object at the beginning of the Queue without removing it.
Synchronized(Queue queue) Returns a synchronized wrapper for the specified Queue.
ToString() Returns a string that represents the current object.

Example

The following code example demonstrates how to use the Queue class to create a queue, add elements, and remove elements.


using System;
using System.Collections;

public class Example
{
    public static void Main()
    {
        // Create a Queue.
        Queue myQueue = new Queue();

        // Add elements to the queue.
        myQueue.Enqueue("Hello");
        myQueue.Enqueue("World");
        myQueue.Enqueue(123);
        myQueue.Enqueue(true);

        // Display the number of elements in the queue.
        Console.WriteLine("Count: {0}", myQueue.Count);

        // Peek at the element at the beginning of the queue.
        Console.WriteLine("Peek: {0}", myQueue.Peek());

        // Remove and display elements from the queue.
        Console.WriteLine("Dequeue: {0}", myQueue.Dequeue());
        Console.WriteLine("Dequeue: {0}", myQueue.Dequeue());

        // Display the remaining elements in the queue.
        Console.WriteLine("Remaining elements:");
        foreach (object obj in myQueue)
        {
            Console.WriteLine(obj);
        }

        // Clear the queue.
        myQueue.Clear();
        Console.WriteLine("Count after Clear: {0}", myQueue.Count);
    }
}
Inheritance Hierarchy ►

Object
     Queue

Implements ►

ICollection, IEnumerable, IQueue