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File.Copy Method (String, String, Boolean)

Updated: July 2009

Copies an existing file to a new file. Overwriting a file of the same name is allowed.

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

public static void Copy(
	string sourceFileName,
	string destFileName,
	bool overwrite
)

Parameters

sourceFileName
Type: System.String

The file to copy.

destFileName
Type: System.String

The name of the destination file. This cannot be a directory.

overwrite
Type: System.Boolean

true if the destination file can be overwritten; otherwise, false.

ExceptionCondition
UnauthorizedAccessException

The caller does not have the required permission.

-or-

destFileName is read-only.

ArgumentException

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

-or-

sourceFileName or destFileName specifies a directory.

ArgumentNullException

sourceFileName or destFileName is null.

PathTooLongException

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.

DirectoryNotFoundException

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

FileNotFoundException

sourceFileName was not found.

IOException

destFileName exists and overwrite is false.

-or-

An I/O error has occurred.

NotSupportedException

sourceFileName or destFileName is in an invalid format.

The sourceFileName and destFileName arguments are permitted to specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory.

For a list of common I/O tasks, see Common I/O Tasks.

The following example copies files to the C:\archives\2008 backup folder. It uses the two overloads of the Copy method as follows:

  • It first uses the File.Copy(String, String) method overload to copy text (.txt) files. The code demonstrates that this overload does not allow overwriting files that were already copied.

  • It then uses the File.Copy(String, String, Boolean) method overload to copy pictures (.jpg files). The code demonstrates that this overload does allow overwriting files that were already copied.

string sourceDir = @"c:\current";
string backupDir = @"c:\archives\2008";

try
{
    string[] picList = Directory.GetFiles(sourceDir, "*.jpg");
    string[] txtList = Directory.GetFiles(sourceDir, "*.txt");

    // Copy picture files. 
    foreach (string f in picList)
    {
        // Remove path from the file name.
        string fName = f.Substring(sourceDir.Length + 1);

        // Use the Path.Combine method to safely append the file name to the path. 
        // Will overwrite if the destination file already exists.
        File.Copy(Path.Combine(sourceDir, fName), Path.Combine(backupDir, fName), true);
    }

    // Copy text files. 
    foreach (string f in txtList)
    {

        // Remove path from the file name.
        string fName = f.Substring(sourceDir.Length + 1);

        try
        {
            // Will not overwrite if the destination file already exists.
            File.Copy(Path.Combine(sourceDir, fName), Path.Combine(backupDir, fName));
        }

        // Catch exception if the file was already copied. 
        catch (IOException copyError)
        {
            Console.WriteLine(copyError.Message);
        }
    }

    // Delete source files that were copied. 
    foreach (string f in txtList)
    {
        File.Delete(f);
    }
    foreach (string f in picList)
    {
        File.Delete(f);
    }
}

catch (DirectoryNotFoundException dirNotFound)
{
    Console.WriteLine(dirNotFound.Message);
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

July 2009

Replaced the code example.

Customer feedback.

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