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Queue<T>::Contains Method

Determines whether an element is in the Queue<T>.

Namespace:  System.Collections.Generic
Assembly:  System (in System.dll)

public:
bool Contains(
	T item
)

Parameters

item
Type: T

The object to locate in the Queue<T>. The value can be nullptr for reference types.

Return Value

Type: System::Boolean
true if item is found in the Queue<T>; otherwise, false.

This method determines equality using the default equality comparer EqualityComparer<T>::Default for T, the type of values in the queue.

This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

The following code example demonstrates several methods of the Queue<T> generic class, including the Contains method.

The code example creates a queue of strings with default capacity and uses the Enqueue method to queue five strings. The elements of the queue are enumerated, which does not change the state of the queue. The Dequeue method is used to dequeue the first string. The Peek method is used to look at the next item in the queue, and then the Dequeue method is used to dequeue it.

The ToArray method is used to create an array and copy the queue elements to it, then the array is passed to the Queue<T> constructor that takes IEnumerable<T>, creating a copy of the queue. The elements of the copy are displayed.

An array twice the size of the queue is created, and the CopyTo method is used to copy the array elements beginning at the middle of the array. The Queue<T> constructor is used again to create a second copy of the queue containing three null elements at the beginning.

The Contains method is used to show that the string "four" is in the first copy of the queue, after which the Clear method clears the copy and the Count property shows that the queue is empty.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, 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.

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