StringBuilder.CopyTo 方法

定义

命名空间:

System.Text

程序集:

netstandard.dll, System.Runtime.dll

重载

名称	说明
CopyTo(Int32, Span<Char>, Int32)	将此实例的指定段中的字符复制到目标 Char 范围。
CopyTo(Int32, Char[], Int32, Int32)	将此实例的指定段中的字符复制到目标 Char 数组的指定段。

CopyTo(Int32, Span<Char>, Int32)

Source:

StringBuilder.cs

将此实例的指定段中的字符复制到目标 Char 范围。

public:
 void CopyTo(int sourceIndex, Span<char> destination, int count);

public void CopyTo(int sourceIndex, Span<char> destination, int count);

member this.CopyTo : int * Span<char> * int -> unit

Public Sub CopyTo (sourceIndex As Integer, destination As Span(Of Char), count As Integer)

参数

sourceIndex

Int32

此实例中的起始位置，将从中复制字符。 该索引从零开始。

destination

Span<Char>

将复制字符的可写范围。

count

Int32

要复制的字符数。

注解

当你需要有效地将对象的后续部分StringBuilder复制到范围时，此方法CopyTo在极少数情况下使用。

例如，代码可以使用大量字符填充 StringBuilder 对象，然后使用 CopyTo 该方法将对象的小连续片段 StringBuilder 复制到处理片段的范围。 处理对象中的所有 StringBuilder 数据时，该对象的大小 StringBuilder 设置为零，循环将重复。

CopyTo(Int32, Char[], Int32, Int32)

Source:

StringBuilder.cs

将此实例的指定段中的字符复制到目标 Char 数组的指定段。

public:
 void CopyTo(int sourceIndex, cli::array <char> ^ destination, int destinationIndex, int count);

public void CopyTo(int sourceIndex, char[] destination, int destinationIndex, int count);

member this.CopyTo : int * char[] * int * int -> unit

Public Sub CopyTo (sourceIndex As Integer, destination As Char(), destinationIndex As Integer, count As Integer)

参数

sourceIndex

Int32

此实例中的起始位置，将从中复制字符。 该索引从零开始。

destination

Char[]

将复制字符的数组。

destinationIndex

Int32

将复制字符的起始位置 destination 。 该索引从零开始。

count

Int32

要复制的字符数。

例外

ArgumentNullException

destination 是 null。

ArgumentOutOfRangeException

sourceIndex、 destinationIndex或 count小于零。

-或-

sourceIndex 大于此实例的长度。

ArgumentException

sourceIndex + count 大于此实例的长度。

-或-

destinationIndex + count 大于长度 destination。

示例

以下示例演示了该方法 CopyTo 。

// This example demonstrates the CopyTo(Int32, Char[], Int32, Int32) method.

// Typically the destination array is small, preallocated, and global while
// the StringBuilder is large with programmatically defined data.
// However, for this example both the array and StringBuilder are small
// and the StringBuilder has predefined data.

using System;
using System.Text;

class Sample
{
    protected static char[] dest = new char[6];
    public static void Main()
    {
    StringBuilder src = new StringBuilder("abcdefghijklmnopqrstuvwxyz!");
    dest[1] = ')';
    dest[2] = ' ';

// Copy the source to the destination in 9 pieces, 3 characters per piece.

    Console.WriteLine("\nPiece) Data:");
    for(int ix = 0; ix < 9; ix++)
        {
        dest[0] = ix.ToString()[0];
        src.CopyTo(ix * 3, dest, 3, 3);
        Console.Write("    ");
        Console.WriteLine(dest);
        }
    }
}
/*
This example produces the following results:

Piece) Data:
    0) abc
    1) def
    2) ghi
    3) jkl
    4) mno
    5) pqr
    6) stu
    7) vwx
    8) yz!
*/

// This example demonstrates the CopyTo(Int32, Char[], Int32, Int32) method.

// Typically the destination array is small, preallocated, and global while
// the StringBuilder is large with programmatically defined data.
// However, for this example both the array and StringBuilder are small
// and the StringBuilder has predefined data.

open System.Text

let dest = Array.zeroCreate 6

let src = StringBuilder "abcdefghijklmnopqrstuvwxyz!"
dest[1] <- ')'
dest[2] <- ' '

// Copy the source to the destination in 9 pieces, 3 characters per piece.

printfn "\Piece) Data:"
for i = 0 to 8 do
    dest[0] <- (string i)[0]
    src.CopyTo(i * 3, dest, 3, 3)
    printfn $"    {dest}"

// This example produces the following results:
//       Piece) Data:
//           0) abc
//           1) def
//           2) ghi
//           3) jkl
//           4) mno
//           5) pqr
//           6) stu
//           7) vwx
//           8) yz!

' Typically the destination array is small, preallocated, and global while 
' the StringBuilder is large with programmatically defined data. 
' However, for this example both the array and StringBuilder are small 
' and the StringBuilder has predefined data.

Imports System.Text

Class Sample
   Protected Shared dest(5) As Char
   
   Public Shared Sub Main()
      Dim src As New StringBuilder("abcdefghijklmnopqrstuvwxyz!")
      dest(1) = ")"c
      dest(2) = " "c
      
      ' Copy the source to the destination in 9 pieces, 3 characters per piece.
      Console.WriteLine(vbCrLf & "Piece) Data:")
      Dim ix As Integer
      For ix = 0 To 8
         dest(0) = ix.ToString()(0)
         src.CopyTo(ix * 3, dest, 3, 3)
         Console.Write("    ")
         Console.WriteLine(dest)
      Next ix
   End Sub
End Class
'
' This example produces the following results:
'
' Piece) Data:
'     0) abc
'     1) def
'     2) ghi
'     3) jkl
'     4) mno
'     5) pqr
'     6) stu
'     7) vwx
'     8) yz!

注解

当你需要有效地将对象的后续部分StringBuilder复制到数组时，此方法CopyTo在极少数情况下使用。 该数组应是固定大小、预分配、可重用且可能全局访问的。

例如，代码可以使用大量字符填充 StringBuilder 对象，然后使用 CopyTo 该方法将对象的小连续片段 StringBuilder 复制到处理片段的数组中。 处理对象中的所有 StringBuilder 数据时，该对象的大小 StringBuilder 设置为零，循环将重复。