Queue(T).Enumerator Structure (System.Collections.Generic)

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.NET Framework Class Library
Queue<T>.Enumerator Structure

Enumerates the elements of a Queue<T>.

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

Visual Basic
<SerializableAttribute> _
Public Structure Enumerator _
	Implements IEnumerator(Of T), IDisposable, IEnumerator
C#
[SerializableAttribute]
public struct Enumerator : IEnumerator<T>, 
	IDisposable, IEnumerator
Visual C++
[SerializableAttribute]
public value class Enumerator : IEnumerator<T>, 
	IDisposable, IEnumerator
F#
[<Sealed>]
[<SerializableAttribute>]
type Enumerator =  
    struct
        interface IEnumerator<'T>
        interface IDisposable
        interface IEnumerator
    end

The Queue<T>.Enumerator generic type exposes the following members.

Properties

  Name Description
Public property Supported by the XNA Framework Supported by Portable Class Library Current Gets the element at the current position of the enumerator.
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Methods

  Name Description
Public method Supported by the XNA Framework Supported by Portable Class Library Dispose Releases all resources used by the Queue<T>.Enumerator.
Public method Supported by the XNA Framework Supported by Portable Class Library Equals Indicates whether this instance and a specified object are equal. (Inherited from ValueType.)
Protected method Supported by the XNA Framework Supported by Portable Class Library Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method Supported by the XNA Framework Supported by Portable Class Library GetHashCode Returns the hash code for this instance. (Inherited from ValueType.)
Public method Supported by the XNA Framework Supported by Portable Class Library GetType Gets the Type of the current instance. (Inherited from Object.)
Protected method Supported by the XNA Framework Supported by Portable Class Library MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method Supported by the XNA Framework Supported by Portable Class Library MoveNext Advances the enumerator to the next element of the Queue<T>.
Public method Supported by the XNA Framework Supported by Portable Class Library ToString Returns the fully qualified type name of this instance. (Inherited from ValueType.)

In XNA Framework 3.0, this member is inherited from Object.ToString().


In Portable Class Library Portable Class Library, this member is inherited from Object.ToString().
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Explicit Interface Implementations

  Name Description
Explicit interface implemetation Private property Supported by the XNA Framework Supported by Portable Class Library IEnumerator.Current Gets the element at the current position of the enumerator.
Explicit interface implemetation Private method Supported by the XNA Framework Supported by Portable Class Library IEnumerator.Reset Sets the enumerator to its initial position, which is before the first element in the collection.
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Remarks

The foreach statement of the C# language (for each in C++, For Each in Visual Basic) hides the complexity of the enumerators. Therefore, using foreach is recommended, instead of directly manipulating the enumerator.

Enumerators can be used to read the data in the collection, but they cannot be used to modify the underlying collection.

Initially, the enumerator is positioned before the first element in the collection. At this position, Current is undefined. Therefore, you must call MoveNext to advance the enumerator to the first element of the collection before reading the value of Current.

Current returns the same object until MoveNext is called. MoveNext sets Current to the next element.

If MoveNext passes the end of the collection, the enumerator is positioned after the last element in the collection and MoveNext returns false. When the enumerator is at this position, subsequent calls to MoveNext also return false. If the last call to MoveNext returned false, Current is undefined. You cannot set Current to the first element of the collection again; you must create a new enumerator instance instead.

An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated and its behavior is undefined.

The enumerator does not have exclusive access to the collection; therefore, enumerating through a collection is intrinsically not a thread-safe procedure. To guarantee thread safety during enumeration, you can lock the collection during the entire enumeration. To allow the collection to be accessed by multiple threads for reading and writing, you must implement your own synchronization.

Default implementations of collections in System.Collections.Generic are not synchronized.

Version Information

.NET Framework

Supported in: 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
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
See Also

Reference