C＃/ SQL：データベースファイルのコピーと置換によるバックアップと復元？

解決策：

まず、データベースファイルをコピーまたは置換する前に、データベースをオフライン状態に設定し、終了後にオンラインに戻す必要があることを知っておく必要があります。

1）使用した方法

 // fullPath : the path for your database
 // executablePath : the path for your exe folder

    void setFullPath()
    {
        string executable = System.Reflection.Assembly.GetExecutingAssembly().Location;
        executablePath = (System.IO.Path.GetDirectoryName(executable));
        fullPath = executablePath + "\\Database.mdf";
    }

    void takeOffline(string fullPath)
    {
        homeObject.connection.Open();
        homeObject.cmd.CommandText = "ALTER DATABASE [" + fullPath + "] SET OFFLINE";
        homeObject.cmd.ExecuteNonQuery();
        homeObject.cmd.Clone();
    }

    void bringOnline(string fullPath)
    {
        homeObject.cmd.CommandText = "ALTER DATABASE [" + fullPath + "] SET ONLINE"; ;
        homeObject.cmd.ExecuteNonQuery();
        homeObject.cmd.Clone();
        homeObject.connection.Close();
    }

2）データベースファイルのコピー/バックアップ

  bool getDatabaseCopy()
    {
        try
        {
            //
            takeOffline(fullPath);

            // copy database.mdf
            copyDBMDF();

            // copy database_log.ldf
            copyDB_logLDF();

            //
            bringOnline(fullPath);

            return true;
        }
        catch
        {
            //
        }

        return false;
    }

    // txtPath.txt :
    // folder location to save database files in

    void copyDBMDF()
    {
        string fileName = "Database.mdf";

        string sourceFile = fullPath;
        string targetPath = txtPath.Text;

        // Use Path class to manipulate file and directory paths.
        string destFile = System.IO.Path.Combine(targetPath, fileName);

        // To copy a folder's contents to a new location:
        // Create a new target folder, if necessary.
        if (!System.IO.Directory.Exists(targetPath))
        {
            System.IO.Directory.CreateDirectory(targetPath);
        }

        // To copy a file to another location and 
        // overwrite the destination file if it already exists.
        System.IO.File.Copy(sourceFile, destFile, true);
    }

    void copyDB_logLDF()
    {
        string fileName = "Database_log.ldf";

        string sourcePath = executablePath;
        string targetPath = txtPath.Text;

        // Use Path class to manipulate file and directory paths.
        string sourceFile = System.IO.Path.Combine(sourcePath, fileName);
        string destFile = System.IO.Path.Combine(targetPath, fileName);

        // To copy a folder's contents to a new location:
        // Create a new target folder, if necessary.
        if (!System.IO.Directory.Exists(targetPath))
        {
            System.IO.Directory.CreateDirectory(targetPath);
        }

        // To copy a file to another location and 
        // overwrite the destination file if it already exists.
        System.IO.File.Copy(sourceFile, destFile, true);
    }

3）現在のデータベースファイルをコピー/復元したファイルに置き換えます

  bool restoreTheBackup()
    {
        try
        {
            //
            takeOffline(fullPath);

            // load .mdf
            loadMDFDatabaseFile();

            // load _log.ldf
            loadLDFDatabaseFile();

            //
            bringOnline(fullPath);

            return true;
        }
        catch
        {
            //
        }

        return false;
    }

// txtPath.txt :
// location to get database files from to replace with current files.

    void loadLDFDatabaseFile()
    {
        string fileName = "Database_log.ldf";

        string targetPath = executablePath;
        string sourcePath = txtPath.Text;

        // Use Path class to manipulate file and directory paths.
        string sourceFile = System.IO.Path.Combine(sourcePath, fileName);
        string destFile = System.IO.Path.Combine(targetPath, fileName);

        // To copy a folder's contents to a new location:
        // Create a new target folder, if necessary.
        if (!System.IO.Directory.Exists(targetPath))
        {
            System.IO.Directory.CreateDirectory(targetPath);
        }

        // To copy a file to another location and 
        // overwrite the destination file if it already exists.
        System.IO.File.Copy(sourceFile, destFile, true);
    }

    void loadMDFDatabaseFile()
    {
        string fileName = "Database.mdf";

        string targetPath = executablePath;
        string sourcePath = txtPath.Text;

        // Use Path class to manipulate file and directory paths.
        string sourceFile = System.IO.Path.Combine(sourcePath, fileName);
        string destFile = System.IO.Path.Combine(targetPath, fileName);

        // To copy a folder's contents to a new location:
        // Create a new target folder, if necessary.
        if (!System.IO.Directory.Exists(targetPath))
        {
            System.IO.Directory.CreateDirectory(targetPath);
        }

        // To copy a file to another location and 
        // overwrite the destination file if it already exists.
        System.IO.File.Copy(sourceFile, destFile, true);
    }