List<T>.CopyTo 方法

定义

List<T> 或它的一部分复制到一个数组中。Copies the List<T> or a portion of it to an array.

重载

CopyTo(T[], Int32)

从目标数组的指定索引处开始,将整个 List<T> 复制到兼容的一维数组。Copies the entire List<T> to a compatible one-dimensional array, starting at the specified index of the target array.

CopyTo(Int32, T[], Int32, Int32)

从目标数组的指定索引处开始,将元素的范围从 List<T> 复制到兼容的一维数组。Copies a range of elements from the List<T> to a compatible one-dimensional array, starting at the specified index of the target array.

CopyTo(T[])

从目标数组的开头开始,将整个 List<T> 复制到兼容的一维数组。Copies the entire List<T> to a compatible one-dimensional array, starting at the beginning of the target array.

CopyTo(T[], Int32)

从目标数组的指定索引处开始,将整个 List<T> 复制到兼容的一维数组。Copies the entire List<T> to a compatible one-dimensional array, starting at the specified index of the target array.

public:
 virtual void CopyTo(cli::array <T> ^ array, int arrayIndex);
public void CopyTo (T[] array, int arrayIndex);
abstract member CopyTo : 'T[] * int -> unit
override this.CopyTo : 'T[] * int -> unit
Public Sub CopyTo (array As T(), arrayIndex As Integer)

参数

array
T[]

作为从 Array 复制的元素目标的一维 List<T>The one-dimensional Array that is the destination of the elements copied from List<T>. Array 必须具有从零开始的索引。The Array must have zero-based indexing.

arrayIndex
Int32

array 中自其开始复制的从零开始的索引。The zero-based index in array at which copying begins.

实现

异常

arraynullarray is null.

arrayIndex 小于 0。arrayIndex is less than 0.

List<T> 中的元素个数大于从 arrayIndex 到目标 array 末尾之间的可用空间。The number of elements in the source List<T> is greater than the available space from arrayIndex to the end of the destination array.

示例

下面的示例演示 CopyTo 方法的所有三个重载。The following example demonstrates all three overloads of the CopyTo method. 创建字符串的 List<T>,并使用5个字符串填充。A List<T> of strings is created and populated with 5 strings. 创建了15个元素的空字符串数组,CopyTo(T[]) 方法重载用于将列表中的所有元素复制到数组(从数组的第一个元素开始)。An empty string array of 15 elements is created, and the CopyTo(T[]) method overload is used to copy all the elements of the list to the array beginning at the first element of the array. CopyTo(T[], Int32) 方法重载用于将列表中的所有元素复制到数组索引6(索引5为空)开始的数组。The CopyTo(T[], Int32) method overload is used to copy all the elements of the list to the array beginning at array index 6 (leaving index 5 empty). 最后,CopyTo(Int32, T[], Int32, Int32) 方法重载用于将从索引2开始的列表中的3个元素复制到数组索引12(索引11为空)开始的数组中。Finally, the CopyTo(Int32, T[], Int32, Int32) method overload is used to copy 3 elements from the list, beginning with index 2, to the array beginning at array index 12 (leaving index 11 empty). 然后,将显示数组的内容。The contents of the array are then displayed.

using namespace System;
using namespace System::Collections::Generic;

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();

    dinosaurs->Add("Tyrannosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Brachiosaurus");
    dinosaurs->Add("Compsognathus");

    Console::WriteLine();
    for each(String^ dinosaurs in dinosaurs )
    {
        Console::WriteLine(dinosaurs);
    }

    // Create an array of 15 strings.
    array<String^>^ arr = gcnew array<String^>(15);

    dinosaurs->CopyTo(arr);
    dinosaurs->CopyTo(arr, 6);
    dinosaurs->CopyTo(2, arr, 12, 3);

    Console::WriteLine("\nContents of the array:");
    for each(String^ dinosaurs in arr )
    {
        Console::WriteLine(dinosaurs);
    }
}

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

IndexOf("Tyrannosaurus"): 0

IndexOf("Tyrannosaurus", 3): 5

IndexOf("Tyrannosaurus", 2, 2): -1
 */
using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        dinosaurs.Add("Tyrannosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Brachiosaurus");
        dinosaurs.Add("Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        // Declare an array with 15 elements.
        string[] array = new string[15];

        dinosaurs.CopyTo(array);
        dinosaurs.CopyTo(array, 6);
        dinosaurs.CopyTo(2, array, 12, 3);

        Console.WriteLine("\nContents of the array:");
        foreach(string dinosaur in array)
        {
            Console.WriteLine(dinosaur);
        }
    }
}

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Contents of the array:
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Mamenchisaurus
Brachiosaurus
Compsognathus
 */
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Tyrannosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Brachiosaurus")
        dinosaurs.Add("Compsognathus")

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        ' Declare an array with 15 elements (0 through 14).
        Dim array(14) As String

        dinosaurs.CopyTo(array)
        dinosaurs.CopyTo(array, 6)
        dinosaurs.CopyTo(2, array, 12, 3)

        Console.WriteLine(vbLf & "Contents of the array:")
        For Each dinosaur As String In array
            Console.WriteLine(dinosaur)
        Next

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Contents of the array:
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Mamenchisaurus
'Brachiosaurus
'Compsognathus

注解

此方法使用 Array.Copy 复制元素。This method uses Array.Copy to copy the elements.

元素按枚举器循环访问 List<T>的相同顺序复制到 ArrayThe elements are copied to the Array in the same order in which the enumerator iterates through the List<T>.

此方法的运算复杂度为 O (n),其中nCountThis method is an O(n) operation, where n is Count.

CopyTo(Int32, T[], Int32, Int32)

从目标数组的指定索引处开始,将元素的范围从 List<T> 复制到兼容的一维数组。Copies a range of elements from the List<T> to a compatible one-dimensional array, starting at the specified index of the target array.

public:
 void CopyTo(int index, cli::array <T> ^ array, int arrayIndex, int count);
public void CopyTo (int index, T[] array, int arrayIndex, int count);
member this.CopyTo : int * 'T[] * int * int -> unit
Public Sub CopyTo (index As Integer, array As T(), arrayIndex As Integer, count As Integer)

参数

index
Int32

复制即从源 List<T> 中从零开始的索引开始。The zero-based index in the source List<T> at which copying begins.

array
T[]

作为从 Array 复制的元素目标的一维 List<T>The one-dimensional Array that is the destination of the elements copied from List<T>. Array 必须具有从零开始的索引。The Array must have zero-based indexing.

arrayIndex
Int32

array 中自其开始复制的从零开始的索引。The zero-based index in array at which copying begins.

count
Int32

要复制的元素数。The number of elements to copy.

异常

arraynullarray is null.

index 小于 0。index is less than 0.

-或--or- arrayIndex 小于 0。arrayIndex is less than 0.

-或--or- count 小于 0。count is less than 0.

index 等于或大于源 CountList<T>index is equal to or greater than the Count of the source List<T>.

-或--or- index 到源 List<T> 的末尾的元素数大于从 arrayIndex 到目标 array 的末尾的可用空间。The number of elements from index to the end of the source List<T> is greater than the available space from arrayIndex to the end of the destination array.

示例

下面的示例演示 CopyTo 方法的所有三个重载。The following example demonstrates all three overloads of the CopyTo method. 创建字符串的 List<T>,并使用5个字符串填充。A List<T> of strings is created and populated with 5 strings. 创建了15个元素的空字符串数组,CopyTo(T[]) 方法重载用于将列表中的所有元素复制到数组(从数组的第一个元素开始)。An empty string array of 15 elements is created, and the CopyTo(T[]) method overload is used to copy all the elements of the list to the array beginning at the first element of the array. CopyTo(T[], Int32) 方法重载用于将列表中的所有元素复制到数组索引6(索引5为空)开始的数组。The CopyTo(T[], Int32) method overload is used to copy all the elements of the list to the array beginning at array index 6 (leaving index 5 empty). 最后,CopyTo(Int32, T[], Int32, Int32) 方法重载用于将从索引2开始的列表中的3个元素复制到数组索引12(索引11为空)开始的数组中。Finally, the CopyTo(Int32, T[], Int32, Int32) method overload is used to copy 3 elements from the list, beginning with index 2, to the array beginning at array index 12 (leaving index 11 empty). 然后,将显示数组的内容。The contents of the array are then displayed.

using namespace System;
using namespace System::Collections::Generic;

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();

    dinosaurs->Add("Tyrannosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Brachiosaurus");
    dinosaurs->Add("Compsognathus");

    Console::WriteLine();
    for each(String^ dinosaurs in dinosaurs )
    {
        Console::WriteLine(dinosaurs);
    }

    // Create an array of 15 strings.
    array<String^>^ arr = gcnew array<String^>(15);

    dinosaurs->CopyTo(arr);
    dinosaurs->CopyTo(arr, 6);
    dinosaurs->CopyTo(2, arr, 12, 3);

    Console::WriteLine("\nContents of the array:");
    for each(String^ dinosaurs in arr )
    {
        Console::WriteLine(dinosaurs);
    }
}

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

IndexOf("Tyrannosaurus"): 0

IndexOf("Tyrannosaurus", 3): 5

IndexOf("Tyrannosaurus", 2, 2): -1
 */
using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        dinosaurs.Add("Tyrannosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Brachiosaurus");
        dinosaurs.Add("Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        // Declare an array with 15 elements.
        string[] array = new string[15];

        dinosaurs.CopyTo(array);
        dinosaurs.CopyTo(array, 6);
        dinosaurs.CopyTo(2, array, 12, 3);

        Console.WriteLine("\nContents of the array:");
        foreach(string dinosaur in array)
        {
            Console.WriteLine(dinosaur);
        }
    }
}

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Contents of the array:
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Mamenchisaurus
Brachiosaurus
Compsognathus
 */
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Tyrannosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Brachiosaurus")
        dinosaurs.Add("Compsognathus")

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        ' Declare an array with 15 elements (0 through 14).
        Dim array(14) As String

        dinosaurs.CopyTo(array)
        dinosaurs.CopyTo(array, 6)
        dinosaurs.CopyTo(2, array, 12, 3)

        Console.WriteLine(vbLf & "Contents of the array:")
        For Each dinosaur As String In array
            Console.WriteLine(dinosaur)
        Next

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Contents of the array:
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Mamenchisaurus
'Brachiosaurus
'Compsognathus

注解

此方法使用 Array.Copy 复制元素。This method uses Array.Copy to copy the elements.

元素按枚举器循环访问 List<T>的相同顺序复制到 ArrayThe elements are copied to the Array in the same order in which the enumerator iterates through the List<T>.

此方法的运算复杂度为 O (n),其中ncountThis method is an O(n) operation, where n is count.

CopyTo(T[])

从目标数组的开头开始,将整个 List<T> 复制到兼容的一维数组。Copies the entire List<T> to a compatible one-dimensional array, starting at the beginning of the target array.

public:
 void CopyTo(cli::array <T> ^ array);
public void CopyTo (T[] array);
member this.CopyTo : 'T[] -> unit
Public Sub CopyTo (array As T())

参数

array
T[]

作为从 Array 复制的元素目标的一维 List<T>The one-dimensional Array that is the destination of the elements copied from List<T>. Array 必须具有从零开始的索引。The Array must have zero-based indexing.

异常

arraynullarray is null.

List<T> 中的元素个数大于目标 array 可以包含的元素个数。The number of elements in the source List<T> is greater than the number of elements that the destination array can contain.

示例

下面的示例演示 CopyTo 方法的所有三个重载。The following example demonstrates all three overloads of the CopyTo method. 创建字符串的 List<T>,并使用5个字符串填充。A List<T> of strings is created and populated with 5 strings. 创建了15个元素的空字符串数组,CopyTo(T[]) 方法重载用于将列表中的所有元素复制到数组(从数组的第一个元素开始)。An empty string array of 15 elements is created, and the CopyTo(T[]) method overload is used to copy all the elements of the list to the array beginning at the first element of the array. CopyTo(T[], Int32) 方法重载用于将列表中的所有元素复制到数组索引6(索引5为空)开始的数组。The CopyTo(T[], Int32) method overload is used to copy all the elements of the list to the array beginning at array index 6 (leaving index 5 empty). 最后,CopyTo(Int32, T[], Int32, Int32) 方法重载用于将从索引2开始的列表中的3个元素复制到数组索引12(索引11为空)开始的数组中。Finally, the CopyTo(Int32, T[], Int32, Int32) method overload is used to copy 3 elements from the list, beginning with index 2, to the array beginning at array index 12 (leaving index 11 empty). 然后,将显示数组的内容。The contents of the array are then displayed.

using namespace System;
using namespace System::Collections::Generic;

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();

    dinosaurs->Add("Tyrannosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Brachiosaurus");
    dinosaurs->Add("Compsognathus");

    Console::WriteLine();
    for each(String^ dinosaurs in dinosaurs )
    {
        Console::WriteLine(dinosaurs);
    }

    // Create an array of 15 strings.
    array<String^>^ arr = gcnew array<String^>(15);

    dinosaurs->CopyTo(arr);
    dinosaurs->CopyTo(arr, 6);
    dinosaurs->CopyTo(2, arr, 12, 3);

    Console::WriteLine("\nContents of the array:");
    for each(String^ dinosaurs in arr )
    {
        Console::WriteLine(dinosaurs);
    }
}

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Deinonychus
Tyrannosaurus
Compsognathus

IndexOf("Tyrannosaurus"): 0

IndexOf("Tyrannosaurus", 3): 5

IndexOf("Tyrannosaurus", 2, 2): -1
 */
using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        dinosaurs.Add("Tyrannosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Brachiosaurus");
        dinosaurs.Add("Compsognathus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        // Declare an array with 15 elements.
        string[] array = new string[15];

        dinosaurs.CopyTo(array);
        dinosaurs.CopyTo(array, 6);
        dinosaurs.CopyTo(2, array, 12, 3);

        Console.WriteLine("\nContents of the array:");
        foreach(string dinosaur in array)
        {
            Console.WriteLine(dinosaur);
        }
    }
}

/* This code example produces the following output:

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Contents of the array:
Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Tyrannosaurus
Amargasaurus
Mamenchisaurus
Brachiosaurus
Compsognathus

Mamenchisaurus
Brachiosaurus
Compsognathus
 */
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Tyrannosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Brachiosaurus")
        dinosaurs.Add("Compsognathus")

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        ' Declare an array with 15 elements (0 through 14).
        Dim array(14) As String

        dinosaurs.CopyTo(array)
        dinosaurs.CopyTo(array, 6)
        dinosaurs.CopyTo(2, array, 12, 3)

        Console.WriteLine(vbLf & "Contents of the array:")
        For Each dinosaur As String In array
            Console.WriteLine(dinosaur)
        Next

    End Sub
End Class

' This code example produces the following output:
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Contents of the array:
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Tyrannosaurus
'Amargasaurus
'Mamenchisaurus
'Brachiosaurus
'Compsognathus
'
'Mamenchisaurus
'Brachiosaurus
'Compsognathus

注解

此方法使用 Array.Copy 复制元素。This method uses Array.Copy to copy the elements.

元素按枚举器循环访问 List<T>的相同顺序复制到 ArrayThe elements are copied to the Array in the same order in which the enumerator iterates through the List<T>.

此方法的运算复杂度为 O (n),其中nCountThis method is an O(n) operation, where n is Count.

适用于