File.Copy Method

Definition

Namespace:

System.IO

Assembly:

System.Runtime.dll

Copies an existing file to a new file.

Overloads

Copy(String, String)	Copies an existing file to a new file. Overwriting a file of the same name is not allowed.
Copy(String, String, Boolean)	Copies an existing file to a new file. Overwriting a file of the same name is allowed.

Copy(String, String)

Source:

File.cs

Copies an existing file to a new file. Overwriting a file of the same name is not allowed.

public:
 static void Copy(System::String ^ sourceFileName, System::String ^ destFileName);

public static void Copy (string sourceFileName, string destFileName);

static member Copy : string * string -> unit

Public Shared Sub Copy (sourceFileName As String, destFileName As String)

Parameters

sourceFileName

String

The file to copy.

destFileName

String

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

Exceptions

UnauthorizedAccessException

The caller does not have the required permission.

ArgumentException

sourceFileName or destFileName is a zero-length string, contains only white space, or contains one or more invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.

-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.

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.

-or-

An I/O error has occurred.

NotSupportedException

sourceFileName or destFileName is in an invalid format.

Examples

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);
}

let sourceDir = @"c:\current"
let backupDir = @"c:\archives\2008"

try
    let picList = Directory.GetFiles(sourceDir, "*.jpg")
    let txtList = Directory.GetFiles(sourceDir, "*.txt")

    // Copy picture files.
    for f in picList do
        // Remove path from the file name.
        let 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.
    for f in txtList do
        // Remove path from the file name.
        let 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.
        with
        | :? IOException as copyError -> printfn $"{copyError.Message}"

    // Delete source files that were copied.
    for f in txtList do
        File.Delete f

    for f in picList do
        File.Delete f

// Catch exception if the file was already copied.
with
| :? DirectoryNotFoundException as dirNotFound -> printfn $"{dirNotFound.Message}"

Dim sourceDir As String = "c:\current"
Dim backupDir As String = "c:\archives\2008"

Try
    Dim picList As String() = Directory.GetFiles(sourceDir, "*.jpg")
    Dim txtList As String() = Directory.GetFiles(sourceDir, "*.txt")

    ' Copy picture files.
    For Each f As String In picList
        'Remove path from the file name.
        Dim fName As String = 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)
    Next

    ' Copy text files.
    For Each f As String In txtList

        'Remove path from the file name.
        Dim fName As String = 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 copyError As IOException
            Console.WriteLine(copyError.Message)
        End Try
    Next

    For Each f As String In txtList
        File.Delete(f)
    Next

    For Each f As String In picList
        File.Delete(f)
    Next

Catch dirNotFound As DirectoryNotFoundException
    Console.WriteLine(dirNotFound.Message)
End Try

Remarks

This method is equivalent to the Copy(String, String, Boolean) method overload with the overwrite parameter set to false.

The sourceFileName and destFileName parameters can specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. To obtain the current working directory, see the Directory.GetCurrentDirectory method. This method does not support wildcard characters in the parameters.

The attributes of the original file are retained in the copied file.

See also

• Move(String, String)
• Move(String, String)
• File and Stream I/O
• Reading Text From A File
• How to: Write Text to a File
• How to: Read and Write to a Newly Created Data File

Copy(String, String, Boolean)

Source:

File.cs

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

public:
 static void Copy(System::String ^ sourceFileName, System::String ^ destFileName, bool overwrite);

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

static member Copy : string * string * bool -> unit

Public Shared Sub Copy (sourceFileName As String, destFileName As String, overwrite As Boolean)

Parameters

sourceFileName

String

The file to copy.

destFileName

String

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

overwrite

Boolean

true if the destination file should be replaced if it already exists; otherwise, false.

Exceptions

UnauthorizedAccessException

The caller does not have the required permission.

-or-

destFileName is read-only.

-or-

overwrite is true, destFileName exists and is hidden, but sourceFileName is not hidden.

ArgumentException

sourceFileName or destFileName is a zero-length string, contains only white space, or contains one or more invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.

-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.

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.

Examples

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);
}

let sourceDir = @"c:\current"
let backupDir = @"c:\archives\2008"

try
    let picList = Directory.GetFiles(sourceDir, "*.jpg")
    let txtList = Directory.GetFiles(sourceDir, "*.txt")

    // Copy picture files.
    for f in picList do
        // Remove path from the file name.
        let 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.
    for f in txtList do
        // Remove path from the file name.
        let 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.
        with
        | :? IOException as copyError -> printfn $"{copyError.Message}"

    // Delete source files that were copied.
    for f in txtList do
        File.Delete f

    for f in picList do
        File.Delete f

// Catch exception if the file was already copied.
with
| :? DirectoryNotFoundException as dirNotFound -> printfn $"{dirNotFound.Message}"

Dim sourceDir As String = "c:\current"
Dim backupDir As String = "c:\archives\2008"

Try
    Dim picList As String() = Directory.GetFiles(sourceDir, "*.jpg")
    Dim txtList As String() = Directory.GetFiles(sourceDir, "*.txt")

    ' Copy picture files.
    For Each f As String In picList
        'Remove path from the file name.
        Dim fName As String = 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)
    Next

    ' Copy text files.
    For Each f As String In txtList

        'Remove path from the file name.
        Dim fName As String = 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 copyError As IOException
            Console.WriteLine(copyError.Message)
        End Try
    Next

    For Each f As String In txtList
        File.Delete(f)
    Next

    For Each f As String In picList
        File.Delete(f)
    Next

Catch dirNotFound As DirectoryNotFoundException
    Console.WriteLine(dirNotFound.Message)
End Try

Remarks

The sourceFileName and destFileName parameters can specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. This method does not support wildcard characters in the parameters.

The attributes of the original file are retained in the copied file.

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

See also

• Move(String, String)
• Move(String, String)
• File and Stream I/O
• Reading Text From A File
• How to: Write Text to a File
• How to: Read and Write to a Newly Created Data File