Queue Class

Queue Class

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Namespace

System.Collections

Createable

Yes

Syntax

 Dim   queuevariable   As [New] Queue 

queuevariable (required; Queue object)

The name of the Queue object

Description

A Queue object is a model of a queue. Succinctly put, a queue is a first-in, first-out data structure. (This is often abbreviated FIFO.) Put another way, a queue is a data structure that models a line of items. There is a method for inserting items at the end of the line ( enqueueing ), as well as a method for removing the item that is currently at the front of the line ( dequeueing ). Under this scenario, the next item to be dequeued is the item that was placed in line first hence the term first-in, first-out.

Note that the elements in a Queue object are of type Object.

Queue class members marked with a plus sign (+) are discussed in detail in their own entries.

Public Shared Method

Synchronized

Public Instance Properties

Count +

IsReadOnly

IsSynchronized

SyncRoot

Public Instance Methods

Clone

Contains +

CopyTo +

Dequeue +

Enqueue +

Equals

GetEnumerator

GetHashCode

GetType

Peek +

ToArray +

ToString

Example

Here is a bit of code to illustrate the members of the Queue class:

 ' Define a new queue Dim q As New Queue(  ) ' Queue up some items q.Enqueue("Chopin") q.Enqueue("Mozart") q.Enqueue("Beethoven") ' Is an item in the queue? MsgBox("Beethoven in queue: " & CStr(q.Contains("Beethoven"))) ' Peek at the first item MsgBox("First item in queue is: " & q.Peek.ToString) ' Send queue to an array and display all items Dim s() As Object = q.ToArray(  ) Dim i As Integer For i = 0 To UBound(s)     Console.WriteLine(CStr(s(i))) Next ' Clear queue q.Clear(  ) 

VB.NET/VB 6 Differences

The Queue object is new to the .NET Framework.

See Also

Collection Class, Hashtable Class, Stack Class