String.CopyTo Method

Copies a specified number of characters from a specified position in this instance to a specified position in an array of Unicode characters.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

member CopyTo : 
        sourceIndex:int * 
        destination:char[] * 
        destinationIndex:int * 
        count:int -> unit


Type: System.Int32

The index of the first character in this instance to copy.

Type: System.Char[]

An array of Unicode characters to which characters in this instance are copied.

Type: System.Int32

The index in destination at which the copy operation begins.

Type: System.Int32

The number of characters in this instance to copy to destination.


destination is a null reference (Nothing in Visual Basic).


sourceIndex, destinationIndex, or count is negative


sourceIndex does not identify a position in the current instance.


destinationIndex does not identify a valid index in the destination array.


count is greater than the length of the substring from startIndex to the end of this instance


count is greater than the length of the subarray from destinationIndex to the end of the destination array.

This method copies count characters from the sourceIndex position of this instance to the destinationIndex position of destination character array. This method does not resize the destination character array; it must have a sufficient number of elements to accommodate the copied characters or the method throws an ArgumentOutOfRangeException.

sourceIndex and destinationIndex are zero-based.

The following example demonstrates the CopyTo method.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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