ArraySegment(T) Structure (System)

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.NET Framework Class Library

ArraySegment<T> Structure

Delimits a section of a one-dimensional array.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic

<SerializableAttribute> _
Public Structure ArraySegment(Of T)

[SerializableAttribute]
public struct ArraySegment<T>

Visual C++

[SerializableAttribute]
generic<typename T>
public value class ArraySegment

[<Sealed>]
[<SerializableAttribute>]
type ArraySegment<'T> =  struct end

Type Parameters

T: The type of the elements in the array segment.

The ArraySegment<T> type exposes the following members.

Constructors

	Name	Description
	ArraySegment<T>(T[])	Initializes a new instance of the ArraySegment<T> structure that delimits all the elements in the specified array.
	ArraySegment<T>(T[], Int32, Int32)	Initializes a new instance of the ArraySegment<T> structure that delimits the specified range of the elements in the specified array.

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Properties

	Name	Description
	Array	Gets the original array containing the range of elements that the array segment delimits.
	Count	Gets the number of elements in the range delimited by the array segment.
	Offset	Gets the position of the first element in the range delimited by the array segment, relative to the start of the original array.

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Methods

	Name	Description
	Equals(ArraySegment<T>)	Determines whether the specified ArraySegment<T> structure is equal to the current instance.
	Equals(Object)	Determines whether the specified object is equal to the current instance. (Overrides ValueType.Equals(Object).)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Returns the hash code for the current instance. (Overrides ValueType.GetHashCode().)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	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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Operators

	Name	Description
	Equality	Indicates whether two ArraySegment<T> structures are equal.
	Inequality	Indicates whether two ArraySegment<T> structures are unequal.

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Remarks

ArraySegment<T> is a wrapper around an array that delimits a range of elements in that array. Multiple ArraySegment<T> instances can refer to the same original array and can overlap.

The Array property returns the entire original array, not a copy of the array; therefore, changes made to the array returned by the Array property are made to the original array.

The original array must be one-dimensional and must have zero-based indexing.

Examples

The following code example passes an ArraySegment<T> structure to a method.

Visual Basic


Imports System

Public Class SamplesArray

    Public Shared Sub Main()

        ' Create and initialize a new string array.
        Dim myArr As String() =  {"The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog"}

        ' Display the initial contents of the array.
        Console.WriteLine("The original array initially contains:")
        PrintIndexAndValues(myArr)

        ' Define an array segment that contains the entire array.
        Dim myArrSegAll As New ArraySegment(Of String)(myArr)

        ' Display the contents of the ArraySegment.
        Console.WriteLine("The first array segment (with all the array's elements) contains:")
        PrintIndexAndValues(myArrSegAll)

        ' Define an array segment that contains the middle five values of the array.
        Dim myArrSegMid As New ArraySegment(Of String)(myArr, 2, 5)

        ' Display the contents of the ArraySegment.
        Console.WriteLine("The second array segment (with the middle five elements) contains:")
        PrintIndexAndValues(myArrSegMid)

        ' Modify the fourth element of the first array segment myArrSegAll.
        myArrSegAll.Array(3) = "LION"

        ' Display the contents of the second array segment myArrSegMid.
        ' Note that the value of its second element also changed.
        Console.WriteLine("After the first array segment is modified, the second array segment now contains:")
        PrintIndexAndValues(myArrSegMid)

    End Sub 'Main

    Public Shared Sub PrintIndexAndValues(arrSeg As ArraySegment(Of String))
        Dim i As Integer
        For i = arrSeg.Offset To (arrSeg.Offset + arrSeg.Count - 1)
            Console.WriteLine("   [{0}] : {1}", i, arrSeg.Array(i))
        Next i
        Console.WriteLine()
    End Sub 'PrintIndexAndValues 

    Public Shared Sub PrintIndexAndValues(myArr as String())
        Dim i As Integer
        For i = 0 To (myArr.Length - 1)
            Console.WriteLine("   [{0}] : {1}", i, myArr(i))
        Next i
        Console.WriteLine()
    End Sub 'PrintIndexAndValues 

End Class 'SamplesArray


'This code produces the following output.
'
'The original array initially contains:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'The first array segment (with all the array's elements) contains:
'   [0] : The
'   [1] : quick
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'   [7] : lazy
'   [8] : dog
'
'The second array segment (with the middle five elements) contains:
'   [2] : brown
'   [3] : fox
'   [4] : jumps
'   [5] : over
'   [6] : the
'
'After the first array segment is modified, the second array segment now contains:
'   [2] : brown
'   [3] : LION
'   [4] : jumps
'   [5] : over
'   [6] : the


using System;

public class SamplesArray  {

   public static void Main()  {

      // Create and initialize a new string array.
      String[] myArr = { "The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog" };

      // Display the initial contents of the array.
      Console.WriteLine( "The original array initially contains:" );
      PrintIndexAndValues( myArr );

      // Define an array segment that contains the entire array.
      ArraySegment<String> myArrSegAll = new ArraySegment<String>( myArr );

      // Display the contents of the ArraySegment.
      Console.WriteLine( "The first array segment (with all the array's elements) contains:" );
      PrintIndexAndValues( myArrSegAll );

      // Define an array segment that contains the middle five values of the array.
      ArraySegment<String> myArrSegMid = new ArraySegment<String>( myArr, 2, 5 );

      // Display the contents of the ArraySegment.
      Console.WriteLine( "The second array segment (with the middle five elements) contains:" );
      PrintIndexAndValues( myArrSegMid );

      // Modify the fourth element of the first array segment myArrSegAll.
      myArrSegAll.Array[3] = "LION";

      // Display the contents of the second array segment myArrSegMid.
      // Note that the value of its second element also changed.
      Console.WriteLine( "After the first array segment is modified, the second array segment now contains:" );
      PrintIndexAndValues( myArrSegMid );

   }

   public static void PrintIndexAndValues( ArraySegment<String> arrSeg )  {
      for ( int i = arrSeg.Offset; i < (arrSeg.Offset + arrSeg.Count); i++ )  {
         Console.WriteLine( "   [{0}] : {1}", i, arrSeg.Array[i] );
      }
      Console.WriteLine();
   }

   public static void PrintIndexAndValues( String[] myArr )  {
      for ( int i = 0; i < myArr.Length; i++ )  {
         Console.WriteLine( "   [{0}] : {1}", i, myArr[i] );
      }
      Console.WriteLine();
   }

}


/* 
This code produces the following output.

The original array initially contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The first array segment (with all the array's elements) contains:
   [0] : The
   [1] : quick
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the
   [7] : lazy
   [8] : dog

The second array segment (with the middle five elements) contains:
   [2] : brown
   [3] : fox
   [4] : jumps
   [5] : over
   [6] : the

After the first array segment is modified, the second array segment now contains:
   [2] : brown
   [3] : LION
   [4] : jumps
   [5] : over
   [6] : the

*/

Visual C++


using namespace System;


namespace Sample
{
    public ref class SampleArray  
    {
    public:
        static void Work()  
        {

            // Create and initialize a new string array.
            array <String^>^ words = {"The", "quick", "brown",
                "fox", "jumps", "over", "the", "lazy", "dog"};

            // Display the initial contents of the array.
            Console::WriteLine("The first array segment"
		        " (with all the array's elements) contains:");
            PrintIndexAndValues(words);

            // Define an array segment that contains the entire array.
            ArraySegment<String^> segment(words);
			
            // Display the contents of the ArraySegment.
            Console::WriteLine("The first array segment"
                " (with all the array's elements) contains:");
            PrintIndexAndValues(segment);

            // Define an array segment that contains the middle five 
            // values of the array.
            ArraySegment<String^> middle(words, 2, 5);

            // Display the contents of the ArraySegment.
            Console::WriteLine("The second array segment"
                " (with the middle five elements) contains:");
            PrintIndexAndValues(middle);

            // Modify the fourth element of the first array 
            // segment
            segment.Array[3] = "LION";

            // Display the contents of the second array segment 
            // middle. Note that the value of its second element 
            // also changed.
            Console::WriteLine("After the first array segment"
                " is modified,the second array segment"
                " now contains:");
            PrintIndexAndValues(middle);
            Console::ReadLine();
        }

        static void PrintIndexAndValues(ArraySegment<String^>^ segment)  
        {
            for (int i = segment->Offset; 
                i < (segment->Offset + segment->Count); i++)  
            {
                Console::WriteLine("   [{0}] : {1}", i,
                    segment->Array[i]);
            }
            Console::WriteLine();
        }

        static void PrintIndexAndValues(array<String^>^ words) 
        {
            for (int i = 0; i < words->Length; i++)  
            {
                Console::WriteLine("   [{0}] : {1}", i,
                    words[i]);
            }
            Console::WriteLine();
        }
    };
}

int main()
{
    Sample::SampleArray::Work();
    return 0; 
}


    /* 
    This code produces the following output.

    The original array initially contains:
    [0] : The
    [1] : quick
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the
    [7] : lazy
    [8] : dog

    The first array segment (with all the array's elements) contains:
    [0] : The
    [1] : quick
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the
    [7] : lazy
    [8] : dog

    The second array segment (with the middle five elements) contains:
    [2] : brown
    [3] : fox
    [4] : jumps
    [5] : over
    [6] : the

    After the first array segment is modified, the second array segment now contains:
    [2] : brown
    [3] : LION
    [4] : jumps
    [5] : over
    [6] : the

    */

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.

Reference

System Namespace

System.Array