文件事物管理Transactional File Manager的实例详解

// Wrap a file copy and a database insert in the same transactionTxFileManager fileMgr = new TxFileManager();using (TransactionScope scope1 = new TransactionScope())

{// Copy a file

fileMgr.Copy(srcFileName, destFileName);// Insert a database record

dbMgr.ExecuteNonQuery(insertSql);scope1.Complete();

}

// Completely unrealistic example showing how various file operations, including operations done // by library/3rd party code, can participate in transactions.IFileManager fileManager = new TxFileManager();using (TransactionScope scope1 = new TransactionScope())

{    fileManager.WriteAllText(inFileName, xml);    // Snapshot allows any file operation to be part of our transaction.

    // All we need to know is the file name.

    //The statement below tells the TxFileManager to remember the state of this file.

    // So even though XslCompiledTransform has no knowledge of our TxFileManager, the file it creates (outFileName)

    // will still be restored to this state in the event of a rollback.

    fileManager.Snapshot(outFileName);    XslCompiledTransform xsl = new XslCompiledTransform(true);    xsl.Load(uri);    xsl.Transform(inFileName, outFileName);    // write to database 1. This database op will get committed/rolled back along with the file operations we are doing in this transaction.

    myDb1.ExecuteNonQuery(sql1);    // write to database 2. The transaction is promoted to a distributed transaction here.

    myDb2.ExecuteNonQuery(sql2);    // let's delete some files

    for (string fileName in filesToDelete)

    {

        fileManager.Delete(fileName);

    }    // Just for kicks, let's start a new nested  transaction. Since we specify RequiresNew here, this nested transaction

    // will be committed/rolled back separately from the main transaction.

    // Note that we can still use the same fileManager instance. It knows how to sort things out correctly.

    using (TransactionScope scope2 = new TransactionScope(TransactionScopeOptions.RequiresNew))

    {        fileManager.MoveFile(anotherFile, anotherFileDest);

    }    // move some files

    for (string fileName in filesToMove)

    {

        fileManager.Move(fileName, GetNewFileName(fileName));

    }    // Finally, let's create a few temporary files...

    // disk space has to be used for something.

    // The nice thing about FileManager.GetTempFileName is that

    // The temp file will be cleaned up automatically for you when the TransactionScope completes.

    // No more worries about temp files that get left behind.

    for (int i=0; i<10; i++)

    {

        fileManager.WriteAllText(fileManager.GetTempFileName(), "testing 1 2");

    }    scope1.Complete();    // In the event an exception occurs, everything done here will be rolled back including the output xsl file.}