Open File in a class and have access to it in another class

[mikrocat]

Hi,

In my Dialogclass I open a file

if(file.open(QIODevice::ReadOnly | QIODevice::Text)){
        ui->FileEdit->setText(filepath);
        QByteArray firstlineArray =  file.readLine();
        ui->UpdateProgressBar->setRange(0,(file.size()-firstlineArray.size()));
        firstlineArray.chop(1);
        devicetypeFromFile = firstlineArray.toInt();
        enableUpdateButton(true);
    }

if(file.open(QIODevice::ReadOnly | QIODevice::Text)){
        ui->FileEdit->setText(filepath);
        QByteArray firstlineArray =  file.readLine();
        ui->UpdateProgressBar->setRange(0,(file.size()-firstlineArray.size()));
        firstlineArray.chop(1);
        devicetypeFromFile = firstlineArray.toInt();
        enableUpdateButton(true);
    }

To copy to clipboard, switch view to plain text mode 

Now I want to have access to this file in my WorkerThread Class, because I need to read some lines from this file (it's a file with many hex-lines). The Dialog starts with a click on a Button the WorkerThread.
What is the best way to get the file to my Worker Thread?