File.Copy 方法

定義

命名空間:

System.IO

組件:

System.Runtime.dll

複製現有的檔案到新的檔案。

多載

Copy(String, String, Boolean)	複製現有的檔案到新的檔案。 允許覆寫相同名稱的檔案。
Copy(String, String)	複製現有的檔案到新的檔案。 不允許覆寫相同名稱的檔案。

Copy(String, String, Boolean)

來源:

File.cs

複製現有的檔案到新的檔案。 允許覆寫相同名稱的檔案。

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)

參數

sourceFileName

String

要複製的檔案。

destFileName

String

目的地檔案的名稱。 這不可以是目錄。

overwrite

Boolean

true 如果目的地檔案已經存在，則為 ;如果目的地檔案已存在，則為 ;否則為 false。

例外狀況

UnauthorizedAccessException

呼叫端沒有必要的權限。

-或-

destFileName 是唯讀的。

-或-

overwrite 是 true，destFileName 存在且為隱藏，但 sourceFileName 不會隱藏。

ArgumentException

sourceFileName 或 destFileName 為零長度字串，只包含空格或包含一或多個無效字元。 您可以使用 GetInvalidPathChars() 方法查詢無效字元。

-或-

sourceFileName 或 destFileName 會指定目錄。

ArgumentNullException

sourceFileName 或 destFileName 為 null。

PathTooLongException

指定的路徑、檔案名稱，或兩者都超出系統定義的長度上限。

DirectoryNotFoundException

sourceFileName 或 destFileName 指定的路徑無效 (例如，它位於未對應的磁碟機上)。

FileNotFoundException

找不到 sourceFileName。

IOException

destFileName 存在，且 overwrite 是 false。

-或-

發生 I/O 錯誤。

NotSupportedException

sourceFileName 或 destFileName 格式無效。

範例

下列範例會將檔案複製到 C：\archives\2008 備份資料夾。 它會使用 方法的兩個 Copy 多載，如下所示：

• 它會先使用 File.Copy(String, String) 方法多載來複製文字 (.txt) 檔案。 此程式代碼示範此多載不允許覆寫已複製的檔案。

然後， File.Copy(String, String, Boolean) 它會使用 方法多載來複製圖片 (.jpg 檔案) 。 此程式代碼示範此多載確實允許覆寫已複製的檔案。

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

備註

sourceFileName和 destFileName 參數可以指定相對或絕對路徑資訊。 相對路徑資訊會解譯為相對於目前工作目錄。 這個方法不支持參數中的通配符。

源檔的屬性會保留在複製的檔案中。

如需一般 I/O 工作的清單，請參閱 一般 I/O 工作。

另請參閱

• Move(String, String)
• Move(String, String)
• 檔案和資料流 I/O
• 從檔案讀取文字
• 作法：將文字寫入檔案
• 作法：讀取和寫入新建立的資料檔案

Copy(String, String)

來源:

File.cs

複製現有的檔案到新的檔案。 不允許覆寫相同名稱的檔案。

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)

參數

sourceFileName

String

要複製的檔案。

destFileName

String

目的地檔案的名稱。 這不可以是目錄或現有檔案。

例外狀況

UnauthorizedAccessException

呼叫端沒有必要的權限。

ArgumentException

sourceFileName 或 destFileName 為零長度字串，只包含空格或包含一或多個無效字元。 您可以使用 GetInvalidPathChars() 方法查詢無效字元。

-或-

sourceFileName 或 destFileName 會指定目錄。

ArgumentNullException

sourceFileName 或 destFileName 為 null。

PathTooLongException

指定的路徑、檔案名稱，或兩者都超出系統定義的長度上限。

DirectoryNotFoundException

sourceFileName 或 destFileName 指定的路徑無效 (例如，它位於未對應的磁碟機上)。

FileNotFoundException

找不到 sourceFileName。

IOException

destFileName 存在。

-或-

發生 I/O 錯誤。

NotSupportedException

sourceFileName 或 destFileName 格式無效。

範例

下列範例會將檔案複製到 C：\archives\2008 備份資料夾。 它會使用 方法的兩個 Copy 多載，如下所示：

• 它會先使用 File.Copy(String, String) 方法多載來複製文字 (.txt) 檔案。 此程式代碼示範此多載不允許覆寫已複製的檔案。

• 然後， File.Copy(String, String, Boolean) 它會使用 方法多載來複製圖片 (.jpg 檔案) 。 此程式代碼示範此多載確實允許覆寫已複製的檔案。

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

備註

這個方法相當於 Copy(String, String, Boolean) 方法多載， overwrite 參數設定為 false。

sourceFileName和 destFileName 參數可以指定相對或絕對路徑資訊。 相對路徑資訊會解譯為相對於目前工作目錄。 若要取得目前的工作目錄，請參閱 Directory.GetCurrentDirectory 方法。 這個方法不支持參數中的通配符。

源檔的屬性會保留在複製的檔案中。

另請參閱

• Move(String, String)
• Move(String, String)
• 檔案和資料流 I/O
• 從檔案讀取文字
• 作法：將文字寫入檔案
• 作法：讀取和寫入新建立的資料檔案