ArraySegment<T> Struktura

Definice

generic <typename T>
public value class ArraySegment : System::Collections::Generic::ICollection<T>, System::Collections::Generic::IEnumerable<T>, System::Collections::Generic::IList<T>, System::Collections::Generic::IReadOnlyCollection<T>, System::Collections::Generic::IReadOnlyList<T>

generic <typename T>
public value class ArraySegment

public struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

public readonly struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

[System.Serializable]
public struct ArraySegment<T>

[System.Serializable]
public struct ArraySegment<T> : System.Collections.Generic.ICollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyCollection<T>, System.Collections.Generic.IReadOnlyList<T>

type ArraySegment<'T> = struct
    interface ICollection<'T>
    interface seq<'T>
    interface IEnumerable
    interface IList<'T>
    interface IReadOnlyCollection<'T>
    interface IReadOnlyList<'T>

[<System.Serializable>]
type ArraySegment<'T> = struct

[<System.Serializable>]
type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>
    interface seq<'T>
    interface IEnumerable

[<System.Serializable>]
type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface seq<'T>
    interface IEnumerable
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>

type ArraySegment<'T> = struct
    interface IList<'T>
    interface ICollection<'T>
    interface IReadOnlyList<'T>
    interface IReadOnlyCollection<'T>
    interface seq<'T>
    interface IEnumerable

Public Structure ArraySegment(Of T)
Implements ICollection(Of T), IEnumerable(Of T), IList(Of T), IReadOnlyCollection(Of T), IReadOnlyList(Of T)

Public Structure ArraySegment(Of T)

Parametry typu

Dědičnost

Object

ValueType

ArraySegment<T>

Atributy

SerializableAttribute

Implementuje

ICollection<T> IEnumerable<T> IList<T> IReadOnlyCollection<T> IReadOnlyList<T> IEnumerable

Příklady

Následující příklad kódu předá ArraySegment<T> strukturu metodě.

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

    */

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

*/

open System

// Print functions.
let printIndexAndValues (myArr: string []) =
    for i = 0 to myArr.Length - 1 do
        printfn $"   [{i}] : {myArr[i]}"
    printfn ""

let printIndexAndValuesSeg (arrSeg: ArraySegment<string>) =
    for i = arrSeg.Offset to arrSeg.Offset + arrSeg.Count - 1 do
        printfn $"   [{i}] : {arrSeg.Array[i]}"
    printfn ""

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

// Display the initial contents of the array.
printfn "The original array initially contains:"
printIndexAndValues myArr

// Define an array segment that contains the entire array.
let myArrSegAll = ArraySegment<string>(myArr)

// Display the contents of the ArraySegment.
printfn "The first array segment (with all the array's elements) contains:"
printIndexAndValuesSeg myArrSegAll

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

// Display the contents of the ArraySegment.
printfn "The second array segment (with the middle five elements) contains:"
printIndexAndValuesSeg 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.
printfn "After the first array segment is modified, the second array segment now contains:"
printIndexAndValuesSeg myArrSegMid


(*
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

*)

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

    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

    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

End Class


'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

Poznámky

ArraySegment<T> je obálka kolem pole, která odděluje oblast prvků v dané matici. Více instancí ArraySegment<T> může odkazovat na stejné původní pole a může se překrývat. Původní pole musí být jednorozměrné a musí mít indexování založené na nule.

Struktura ArraySegment<T> je užitečná, kdykoli budou prvky pole manipulovány v různých segmentech. Například:

• Můžete předat ArraySegment<T> objekt, který představuje pouze část pole jako argument metody, místo volání relativně nákladné metody, jako je Copy předat kopii části pole.

• Ve vícevláknové aplikaci můžete použít strukturu ArraySegment<T>, aby každé vlákno fungovalo pouze na části pole.

• U asynchronních operací založených na úlohách můžete pomocí objektu ArraySegment<T> zajistit, aby každý úkol fungoval na odlišném segmentu pole. Následující příklad rozdělí pole na jednotlivé segmenty s až deseti prvky. Každý prvek v segmentu se vynásobí číslem jeho segmentu. Výsledek ukazuje, že použití třídy ArraySegment<T> k manipulaci s prvky tímto způsobem změní hodnoty jeho podkladového pole.

  using System;
  using System.Collections.Generic;
  using System.Threading.Tasks;
  
  public class Example
  {
     private const int segmentSize = 10;
  
     public static async Task Main()
     {
        List<Task> tasks = new List<Task>();
  
        // Create array.
        int[] arr = new int[50];
        for (int ctr = 0; ctr <= arr.GetUpperBound(0); ctr++)
           arr[ctr] = ctr + 1;
  
        // Handle array in segments of 10.
        for (int ctr = 1; ctr <= Math.Ceiling(((double)arr.Length)/segmentSize); ctr++) {
           int multiplier = ctr;
           int elements = (multiplier - 1) * 10 + segmentSize > arr.Length ?
                           arr.Length - (multiplier - 1) * 10 : segmentSize;
           ArraySegment<int> segment = new ArraySegment<int>(arr, (ctr - 1) * 10, elements);
           tasks.Add(Task.Run( () => { IList<int> list = (IList<int>) segment;
                                       for (int index = 0; index < list.Count; index++)
                                          list[index] = list[index] * multiplier;
                                     } ));
        }
        try {
           await Task.WhenAll(tasks.ToArray());
           int elementsShown = 0;
           foreach (var value in arr) {
              Console.Write("{0,3} ", value);
              elementsShown++;
              if (elementsShown % 18 == 0)
                 Console.WriteLine();
           }
        }
        catch (AggregateException e) {
           Console.WriteLine("Errors occurred when working with the array:");
           foreach (var inner in e.InnerExceptions)
              Console.WriteLine("{0}: {1}", inner.GetType().Name, inner.Message);
        }
     }
  }
  // The example displays the following output:
  //      1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
  //     38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
  //    148 152 156 160 205 210 215 220 225 230 235 240 245 250
  

  open System
  open System.Threading.Tasks
  
  // Create array.
  let arr = Array.init 50 (fun i -> i + 1)
  
  // Handle array in segments of 10.
  let tasks =
      Array.chunkBySize 10 arr
      |> Array.mapi (fun m elements ->
          let mutable segment = ArraySegment<int>(arr, m * 10, elements.Length)
          task {
              for i = 0 to segment.Count - 1 do
                  segment[i] <- segment[i] * (m + 1)
          } :> Task)
  
  try
      Task.WhenAll(tasks).Wait()
      let mutable i = 0
  
      for value in arr do
          printf $"{value, 3} "
          i <- i + 1
          if i % 18 = 0 then printfn ""
  
  with :? AggregateException as e ->
      printfn "Errors occurred when working with the array:"
  
      for inner in e.InnerExceptions do
          printfn $"{inner.GetType().Name}: {inner.Message}"
  
  
  // The example displays the following output:
  //      1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
  //     38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
  //    148 152 156 160 205 210 215 220 225 230 235 240 245 250
  

  Imports System.Collections.Generic
  Imports System.Threading.Tasks
  
  Module Example
    Private Const SegmentSize As Integer = 10
    
     Public Sub Main()
        Dim tasks As New List(Of Task)
        
         ' Create array.
        Dim arr(49) As Integer
        For ctr As Integer = 0 To arr.GetUpperBound(0)
           arr(ctr) = ctr + 1
        Next
  
        ' Handle array in segments of 10.
        For ctr As Integer = 1 To CInt(Math.Ceiling(arr.Length / segmentSize))
           Dim multiplier As Integer = ctr
           Dim elements As Integer = If((multiplier - 1) * 10 + segmentSize > arr.Length,
                                        arr.Length - (multiplier - 1) * 10,
                                        segmentSize)
           Dim segment As New ArraySegment(Of Integer)(arr, (ctr - 1) * 10, elements)
           tasks.Add(Task.Run( Sub()
                                  Dim list As IList(Of Integer) = CType(segment, IList(Of Integer))
                                  For index As Integer = 0 To list.Count - 1
                                     list(index) = list(index) * multiplier
                                  Next
                               End Sub ))
        Next
        Try
           Task.WaitAll(tasks.ToArray())
           Dim elementsShown As Integer = 0
           For Each value In arr
              Console.Write("{0,3} ", value)
              elementsShown += 1
              If elementsShown Mod 18 = 0 Then Console.WriteLine()
           Next
        Catch e As AggregateException
           Console.WriteLine("Errors occurred when working with the array:")
           For Each inner As Exception In e.InnerExceptions
              Console.WriteLine("{0}: {1}", inner.GetType().Name, inner.Message)
           Next
        End Try
     End Sub
  End Module
  ' The example displays the following output:
  '         1   2   3   4   5   6   7   8   9  10  22  24  26  28  30  32  34  36
  '        38  40  63  66  69  72  75  78  81  84  87  90 124 128 132 136 140 144
  '       148 152 156 160 205 210 215 220 225 230 235 240 245 250
  

Všimněte si však, že i když lze ArraySegment<T> strukturu použít k rozdělení pole do odlišných segmentů, segmenty nejsou zcela nezávislé na sobě. Vlastnost Array vrátí celou původní matici, nikoli kopii pole; změny v poli vrácené vlastností Array jsou tedy provedeny v původní matici. Pokud je to nežádoucí, měli byste provádět operace s kopií pole, nikoli s objektem ArraySegment<T>, který představuje část pole.

Metoda Equals a operátory rovnosti a nerovnosti testují rovnost odkazů, když porovnávají dva ArraySegment<T> objekty. Aby byly dva ArraySegment<T> objekty považovány za stejné, musí splňovat všechny následující podmínky:

• Odkaz na stejnou matici

• Začněte ve stejném indexu v poli.

• Mají stejný počet prvků.

Pokud chcete načíst prvek podle jeho indexu v ArraySegment<T> objektu, musíte jej přetypovat na IList<T> objekt a načíst nebo upravit pomocí IList<T>.Item[] vlastnost. Všimněte si, že v jazyce F# to není nutné. Následující příklad načte prvek v ArraySegment<T> objektu, který odděluje oddíl pole řetězce.

using System;
using System.Collections.Generic;

public class Example
{
   public static void Main()
   {
      String[] names = { "Adam", "Bruce", "Charles", "Daniel",
                         "Ebenezer", "Francis", "Gilbert",
                         "Henry", "Irving", "John", "Karl",
                         "Lucian", "Michael" };
      var partNames = new ArraySegment<string>(names, 2, 5);

      // Cast the ArraySegment object to an IList<string> and enumerate it.
      var list = (IList<string>) partNames;
      for (int ctr = 0; ctr <= list.Count - 1; ctr++)
         Console.WriteLine(list[ctr]);
   }
}
// The example displays the following output:
//    Charles
//    Daniel
//    Ebenezer
//    Francis
//    Gilbert

open System

let names = 
    [| "Adam"; "Bruce"; "Charles"; "Daniel"
       "Ebenezer"; "Francis"; "Gilbert"
       "Henry"; "Irving"; "John"; "Karl"
       "Lucian"; "Michael" |]

let partNames = ArraySegment<string>(names, 2, 5)

// Enumerate over the ArraySegment object.
for part in partNames do 
    printfn $"{part}"

// The example displays the following output:
//    Charles
//    Daniel
//    Ebenezer
//    Francis
//    Gilbert

Imports System.Collections.Generic

Module Example
   Public Sub Main()
      Dim names() As String = { "Adam", "Bruce", "Charles", "Daniel", 
                                "Ebenezer", "Francis", "Gilbert", 
                                "Henry", "Irving", "John", "Karl",
                                "Lucian", "Michael" }
      Dim partNames As New ArraySegment(Of String)(names, 2, 5)
      
      ' Cast the ArraySegment object to an IList<String> and enumerate it.
      Dim list = CType(partNames, IList(Of String))
      For ctr As Integer = 0 To list.Count - 1
         Console.WriteLine(list(ctr))
      Next     
   End Sub
End Module
' The example displays the following output:
'    Charles
'    Daniel
'    Ebenezer
'    Francis
'    Gilbert

Konstruktory

Vlastnosti

Metody

Operátory

Explicitní implementace rozhraní

Metody rozšíření

Platí pro

Viz také

• Array