StringBuilder.CopyTo Method

Definition

Namespace:

System.Text

Assembly:

System.Runtime.dll

Overloads

CopyTo(Int32, Char[], Int32, Int32)	Copies the characters from a specified segment of this instance to a specified segment of a destination Char array.
CopyTo(Int32, Span<Char>, Int32)	Copies the characters from a specified segment of this instance to a destination Char span.

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

Source:

StringBuilder.cs

Copies the characters from a specified segment of this instance to a specified segment of a destination Char array.

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)

Parameters

sourceIndex

Int32

The starting position in this instance where characters will be copied from. The index is zero-based.

destination

Char[]

The array where characters will be copied.

destinationIndex

Int32

The starting position in destination where characters will be copied. The index is zero-based.

count

Int32

The number of characters to be copied.

Exceptions

ArgumentNullException

destination is null.

ArgumentOutOfRangeException

sourceIndex, destinationIndex, or count, is less than zero.

-or-

sourceIndex is greater than the length of this instance.

ArgumentException

sourceIndex + count is greater than the length of this instance.

-or-

destinationIndex + count is greater than the length of destination.

Examples

The following example demonstrates the CopyTo method.

// 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 namespace System;
using namespace System::Text;

int main()
{
   array<Char>^dest = gcnew array<Char>(6);
   StringBuilder^ src = gcnew 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.

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!

Remarks

The CopyTo method is intended to be used in the rare situation when you need to efficiently copy successive sections of a StringBuilder object to an array. The array should be a fixed size, preallocated, reusable, and possibly globally accessible.

For example, your code could populate a StringBuilder object with a large number of characters then use the CopyTo method to copy small, successive pieces of the StringBuilder object to an array where the pieces are processed. When all the data in the StringBuilder object is processed, the size of the StringBuilder object is set to zero and the cycle is repeated.

CopyTo(Int32, Span<Char>, Int32)

Source:

StringBuilder.cs

Copies the characters from a specified segment of this instance to a destination Char span.

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)

Parameters

sourceIndex

Int32

The starting position in this instance where characters will be copied from. The index is zero-based.

destination

Span<Char>

The writable span where characters will be copied.

count

Int32

The number of characters to be copied.

Remarks

The CopyTo method is intended to be used in the rare situation when you need to efficiently copy successive sections of a StringBuilder object to an span.

For example, your code could populate a StringBuilder object with a large number of characters then use the CopyTo method to copy small, successive pieces of the StringBuilder object to an span where the pieces are processed. When all the data in the StringBuilder object is processed, the size of the StringBuilder object is set to zero and the cycle is repeated.