问如何在Qt C++中使用QFtp::put上传文件？

EN

QFile *file = new QFile("test.txt");
QFtp *ftp = new QFtp();

if(file->open(QIODevice::ReadWrite)) {
    ftp->setTransferMode(QFtp::Active);
    ftp->connectToHost(server);
    ftp->login(name, password);
    ftp->put(file, "test.txt");
    ftp->close();
}

//ftp.cpp
QFile *file = new QFile("test.txt");
QFtp *ftp = new QFtp();

this->connect(ftp, SIGNAL(commandStarted(int)), SLOT(ftpCommandStarted(int)));
this->connect(ftp, SIGNAL(commandFinished(int, bool)), SLOT(ftpCommandFinished(int, bool)));  
this->connect(ftp, SIGNAL(done(bool)), SLOT(ftpDone(bool)));
this->connect(ftp, SIGNAL(dataTransferProgress(qint64, qint64)), SLOT(ftpDataTransferProgress(qint64, qint64)));
this->connect(ftp, SIGNAL(stateChanged(int)), SLOT(ftpStateChanged(int)));

if(file->open(QIODevice::ReadWrite)) {
    ftp->setTransferMode(QFtp::Active);
    ftp->connectToHost(server);
    ftp->login(name, password);
    ftp->put(file, "test.txt");
    ftp->close();
}

//ftp.h
void ftpCommandStarted(int id);
void ftpCommandFinished(int id, bool error);
void ftpDone(bool);
void ftpDataTransferProgress(qint64, qint64);
void ftpStateChanged(int);

//ftp.cpp
void EmailDialog::ftpCommandStarted(int id) {
    this->messageBox("Command Started: " + QString::number(id));
}

void EmailDialog::ftpCommandFinished(int id, bool error) {
    this->messageBox("Command Finished: " + QString::number(id) + " Error: " + (error ? "Error" : "No Error"));
}

void EmailDialog::ftpDone(bool error) {
    this->messageBox("Done " + QString(error ? "Error" : "No Error"));
}

void EmailDialog::ftpDataTransferProgress(qint64 done, qint64 total) {
    this->messageBox("Done: " + QString::number(done) + " Total: " + QString::number(total));
}

void EmailDialog::ftpStateChanged(int state) {
    QString text;
    switch (state) {
        case 0:
            text = "QFtp::Unconnected";
            break;
        case 1:
            text = "QFtp::HostLookup";
            break;
        case 2:
            text = "QFtp::Connecting";
            break;
        case 3:
            text = "QFtp::Connected";
            break;
        case 4:
            text = "QFtp::LoggingIn";
            break;
        case 5:
            text = "QFtp::Closing";
            break;
        default:
            text = "";
            break;
    }
    this->messageBox(text);
}