QT Designer：打开特定的操作窗口

Question

I'm new to QT Designer and would like to open a specific window from an action. I've searched and all the examples I've seen are like this answer and only give a generic new window, not one that's already predefined. Right now I'm trying to open a predefined window (with header, source, and form) called listcsv right after the file dialog is fulfilled. But the code just makes a generic blank window pop up, not the one I need.

Here's my main window .cpp:

#include "csv_helper.h"
#include "ui_csv_helper.h"
#include "listcsv.h"
#include "ui_listcsv.h"
#include <QFileDialog>
#include <QWindow>

CSV_helper::CSV_helper(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::CSV_helper)
{
    ui->setupUi(this);
}

CSV_helper::~CSV_helper()
{
delete ui;
}

void CSV_helper::on_buttonBox_accepted()
{
    QFileDialog::getOpenFileName(this, tr("Open CSV"),   "/Users/Dropbox", tr("CSV Files (*.csv)"));

    QWidget *listcsv = new QWidget;
    listcsv->show();
    hide();

}

I feel frustrated that this is over something so simple, but nothing on the internet seems to give a straight answer.

Edit: Solved, thanks to john elemans. Just had to modify some things.

void CSV_helper::on_buttonBox_accepted()
{
    QFileDialog::getOpenFileName(this, tr("Open CSV"), "/Users/Dropbox", tr("CSV Files (*.csv)"));

   ListCSV *msd;
   msd = new ListCSV();

   msd->show();
}

Answer 1

Define your new window's layout in a form file with name to match your dialog. Create a new C++ class with a base type of QDialog, called, for example, mySpecialDialog. It should refer the form file as follows; Private: UI::mySpecialDialog ui;

Then in your main code, when you want the dialog,...

    mySpecialDialog *msd;

    msd = new mySpecialDialog();

    if (msd->exec() == QDialog::Accepted)
    {
         ... code 
    }
    else
    {

    }

voila.