Array.GetEnumerator Method
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Returns an IEnumerator for the Array.
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Function GetEnumerator As IEnumerator
public IEnumerator GetEnumerator()
Return Value
Type: System.Collections.IEnumerator
An IEnumerator for the Array.
Implements
Remarks
[Visual Basic, C#]
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. Reset also brings the enumerator back to this position. 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 either MoveNext or Reset 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. To set Current to the first element of the collection again, you can call Reset followed by MoveNext.
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.
This method is an O(1) operation.
Examples
The following code example shows how to use GetEnumerator to list the elements of an array.
Public Class Example
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
' Creates and initializes a new Array.
Dim myArr(10) As [String]
myArr(0) = "The"
myArr(1) = "quick"
myArr(2) = "brown"
myArr(3) = "fox"
myArr(4) = "jumped"
myArr(5) = "over"
myArr(6) = "the"
myArr(7) = "lazy"
myArr(8) = "dog"
' Displays the values of the Array.
Dim i As Integer = 0
Dim myEnumerator As System.Collections.IEnumerator = myArr.GetEnumerator()
outputBlock.Text &= "The Array contains the following values:" & vbCrLf
While myEnumerator.MoveNext() And Not (myEnumerator.Current Is Nothing)
outputBlock.Text += String.Format("[{0}] {1}", i, myEnumerator.Current) & vbCrLf
i += 1
End While
End Sub 'Main
End Class 'SamplesArray
'This code produces the following output.
'
'The Array contains the following values:
'[0] The
'[1] quick
'[2] brown
'[3] fox
'[4] jumped
'[5] over
'[6] the
'[7] lazy
'[8] dog
using System;
public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
// Creates and initializes a new Array.
String[] myArr = new String[10];
myArr[0] = "The";
myArr[1] = "quick";
myArr[2] = "brown";
myArr[3] = "fox";
myArr[4] = "jumped";
myArr[5] = "over";
myArr[6] = "the";
myArr[7] = "lazy";
myArr[8] = "dog";
// Displays the values of the Array.
int i = 0;
System.Collections.IEnumerator myEnumerator = myArr.GetEnumerator();
outputBlock.Text += "The Array contains the following values:" + "\n";
while ((myEnumerator.MoveNext()) && (myEnumerator.Current != null))
outputBlock.Text += String.Format("[{0}] {1}", i++, myEnumerator.Current) + "\n";
}
}
/*
This code produces the following output.
The Array contains the following values:
[0] The
[1] quick
[2] brown
[3] fox
[4] jumped
[5] over
[6] the
[7] lazy
[8] dog
*/
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.