File.Copy Method (String, String)

When it is called by trusted applications, copies an existing file to a new file. Overwriting a file of the same name is not allowed.

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


Public Shared Sub Copy ( _
    sourceFileName As String, _
    destFileName As String _
public static void Copy(
    string sourceFileName,
    string destFileName


  • destFileName
    Type: System.String
    The name of the destination file. This cannot be a directory or an existing file.


Exception Condition

The caller does not have the required permission.


sourceFileName or destFileName is a zero-length string, contains only white space, or contains one or more invalid characters as defined by GetInvalidPathChars.


sourceFileName or destFileName specifies a directory.


sourceFileName or destFileName is nulla null reference (Nothing in Visual Basic).


The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.


The path specified in sourceFileName or destFileName is invalid (for example, it is on an unmapped drive).


sourceFileName was not found.


destFileName exists.


An I/O error has occurred.


sourceFileName or destFileName is in an invalid format.


For more information about trusted applications, see Trusted Applications.

Platform Notes

Silverlight for Windows Phone Silverlight for Windows Phone

 This member has a SecurityCriticalAttribute attribute on Silverlight for Windows Phone, because the attribute was present in Silverlight 3. This attribute restricts this member to internal use. Application code that uses this member throws a MethodAccessException.

Version Information


Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0


For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.