ArrayList.ToArray 方法

定义

命名空间:

System.Collections

程序集:

System.Runtime.dll

将 ArrayList 的元素复制到新数组中。

重载

ToArray()	将 ArrayList 的元素复制到新 Object 数组中。
ToArray(Type)	将 ArrayList 的元素复制到新的指定元素类型数组中。

ToArray()

Source:

ArrayList.cs

将 ArrayList 的元素复制到新 Object 数组中。

public:
 virtual cli::array <System::Object ^> ^ ToArray();

public virtual object?[] ToArray ();

abstract member ToArray : unit -> obj[]
override this.ToArray : unit -> obj[]

Public Overridable Function ToArray () As Object()

返回

Object[]

一个包含 ArrayList 的元素副本的 Object 数组。

注解

使用 Array.Copy复制元素，这是一个 O(n) 操作，其中 n 是 Count。

ToArray(Type)

Source:

ArrayList.cs

将 ArrayList 的元素复制到新的指定元素类型数组中。

public:
 virtual Array ^ ToArray(Type ^ type);

public virtual Array ToArray (Type type);

abstract member ToArray : Type -> Array
override this.ToArray : Type -> Array

Public Overridable Function ToArray (type As Type) As Array

参数

type

Type

要创建和复制元素的目标数组的元素 Type。

返回

Array

包含 ArrayList 的元素副本的指定元素类型数组。

例外

ArgumentNullException

type 为 null。

InvalidCastException

源 ArrayList 的类型无法自动转换为指定类型。

示例

下面的复制示例演示如何将 的 ArrayList 元素复制到字符串数组。

using namespace System;
using namespace System::Collections;
void PrintIndexAndValues( ArrayList^ myList );
void PrintIndexAndValues( array<String^>^myArr );
int main()
{
   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "The" );
   myAL->Add( "quick" );
   myAL->Add( "brown" );
   myAL->Add( "fox" );
   myAL->Add( "jumps" );
   myAL->Add( "over" );
   myAL->Add( "the" );
   myAL->Add( "lazy" );
   myAL->Add( "dog" );

   // Displays the values of the ArrayList.
   Console::WriteLine( "The ArrayList contains the following values:" );
   PrintIndexAndValues( myAL );

   // Copies the elements of the ArrayList to a string array.
   array<String^>^myArr = reinterpret_cast<array<String^>^>(myAL->ToArray( String::typeid ));

   // Displays the contents of the string array.
   Console::WriteLine( "The string array contains the following values:" );
   PrintIndexAndValues( myArr );
}

void PrintIndexAndValues( ArrayList^ myList )
{
   int i = 0;
   IEnumerator^ myEnum = myList->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ o = safe_cast<Object^>(myEnum->Current);
      Console::WriteLine( "\t[{0}]:\t{1}", i++, o );
   }

   Console::WriteLine();
}

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

/* 
This code produces the following output.

The ArrayList contains the following values:
        [0]:    The
        [1]:    quick
        [2]:    brown
        [3]:    fox
        [4]:    jumps
        [5]:    over
        [6]:    the
        [7]:    lazy
        [8]:    dog

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

*/

using System;
using System.Collections;

public class SamplesArrayList  {

   public static void Main()  {

      // Creates and initializes a new ArrayList.
      ArrayList myAL = new ArrayList();
      myAL.Add( "The" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );
      myAL.Add( "jumps" );
      myAL.Add( "over" );
      myAL.Add( "the" );
      myAL.Add( "lazy" );
      myAL.Add( "dog" );

      // Displays the values of the ArrayList.
      Console.WriteLine( "The ArrayList contains the following values:" );
      PrintIndexAndValues( myAL );

      // Copies the elements of the ArrayList to a string array.
      String[] myArr = (String[]) myAL.ToArray( typeof( string ) );

      // Displays the contents of the string array.
      Console.WriteLine( "The string array contains the following values:" );
      PrintIndexAndValues( myArr );
   }

   public static void PrintIndexAndValues( ArrayList myList )  {
      int i = 0;
      foreach ( Object o in myList )
         Console.WriteLine( "\t[{0}]:\t{1}", i++, o );
      Console.WriteLine();
   }

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


/*
This code produces the following output.

The ArrayList contains the following values:
        [0]:    The
        [1]:    quick
        [2]:    brown
        [3]:    fox
        [4]:    jumps
        [5]:    over
        [6]:    the
        [7]:    lazy
        [8]:    dog

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

*/

Imports System.Collections

Public Class SamplesArrayList

    Public Shared Sub Main()

        ' Creates and initializes a new ArrayList.
        Dim myAL As New ArrayList()
        myAL.Add("The")
        myAL.Add("quick")
        myAL.Add("brown")
        myAL.Add("fox")
        myAL.Add("jumps")
        myAL.Add("over")
        myAL.Add("the")
        myAL.Add("lazy")
        myAL.Add("dog")

        ' Displays the values of the ArrayList.
        Console.WriteLine("The ArrayList contains the following values:")
        PrintIndexAndValues(myAL)

        ' Copies the elements of the ArrayList to a string array.
        Dim myArr As String() = CType(myAL.ToArray(GetType(String)), String())

        ' Displays the contents of the string array.
        Console.WriteLine("The string array contains the following values:")
        PrintIndexAndValues(myArr)

    End Sub

    Overloads Public Shared Sub PrintIndexAndValues(myList As ArrayList)
        Dim i As Integer = 0
        Dim o As [Object]
        For Each o In  myList
            Console.WriteLine("        [{0}]:    {1}", i, o)
            i = i + 1
        Next o
        Console.WriteLine()
    End Sub

    Overloads 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 ArrayList contains the following values:
'        [0]:    The
'        [1]:    quick
'        [2]:    brown
'        [3]:    fox
'        [4]:    jumps
'        [5]:    over
'        [6]:    the
'        [7]:    lazy
'        [8]:    dog
'
'The string array contains the following values:
'        [0]:    The
'        [1]:    quick
'        [2]:    brown
'        [3]:    fox
'        [4]:    jumps
'        [5]:    over
'        [6]:    the
'        [7]:    lazy
'        [8]:    dog

注解

对象中的所有 ArrayList 对象都将强制转换为 Type 参数中指定的 type 。

使用 Array.Copy复制元素，这是一个 O(n) 操作，其中 n 是 Count。

另请参阅

• Type