How to capture parent directory from lambda - c++

Question

In my code I list subdirectories name(only child dir) and if i click this subdirectory , the images inside this subdir will be displayed. In my case I cant capture parent directory from inside lambda. How can I do that?
Dir directory = QFileDialog::getExistingDirectory(this, tr("Open Directory"),"/home",
QFileDialog::ShowDirsOnly| QFileDialog::DontResolveSymlinks);
for (const QFileInfo &finfo: directory.entryInfoList()) {
QDir dir(finfo.absoluteFilePath());
ui->listWidget_dirs->addItem(dir.dirName());
}
//QStringList files = directory.entryList(QDir::Dirs);
//ui->listWidget_dirs->addItems(files);
auto listWidget_images = new QListWidget();//set listwidget to display images
listWidget_images->setMinimumSize(1200,400);
listWidget_images->setViewMode(QListWidget::IconMode);
listWidget_images->setIconSize(QSize(320,240));
listWidget_images->setResizeMode(QListWidget::Adjust);
connect(ui->listWidget_dirs, & QListWidget::itemClicked,[listWidget_images,this](QListWidgetItem *item)
{
listWidget_images->show();
listWidget_images->clear();
/*this is where it is wrong*/ QDir path(directory + '/' + item->text());
path.setNameFilters({"*.png", "*.jpg"});
for(const QFileInfo & finfo: path.entryInfoList()){
QListWidgetItem *item = new QListWidgetItem(QIcon(finfo.absoluteFilePath()), finfo.fileName());
listWidget_images->addItem(item);
}
});

Answer 1

I just wanted to leave a note. Be sure that your objects alive during your lamda exist, especially listWidget_images. If you delete it elsewhere, your lamda will crash. I would recommment to change the connect line a little:
from
connect(ui->listWidget_dirs, & QListWidget::itemClicked,[directory,listWidget_images, this](QListWidgetItem *item)
to
connect(ui->listWidget_dirs, & QListWidget::itemClicked, listWidget_images, [directory,listWidget_images, this](QListWidgetItem *item)
If you put the pointer listWidget_images before the capture list [] the lamda will be destroyed, when the object from listWidget_images is destroyed. Otherwise your application will crash in the first line of your lamda if the object doesn't exist anymore.

Answer 2

Well I get how to do it, this is the code.
QDir directory = QFileDialog::getExistingDirectory(this, tr("Open Directory"),"/home",
QFileDialog::ShowDirsOnly| QFileDialog::DontResolveSymlinks);
for (const QFileInfo &finfo: directory.entryInfoList()) {
QDir dir(finfo.absoluteFilePath());
ui->listWidget_dirs->addItem(dir.dirName());
}
auto listWidget_images = new QListWidget();//set listwidget to display images
listWidget_images->setMinimumSize(1200,400);
listWidget_images->setViewMode(QListWidget::IconMode);
listWidget_images->setIconSize(QSize(320,240));
listWidget_images->setResizeMode(QListWidget::Adjust);
connect(ui->listWidget_dirs, & QListWidget::itemClicked,[directory,listWidget_images, this](QListWidgetItem *item)
{
listWidget_images->show();
listWidget_images->clear();
// QDir path(item->text());
QDir dir = directory.absolutePath() + '/' + item->text();
dir.setNameFilters({"*.png", "*.jpg"});
for(const QFileInfo & finfo: dir.entryInfoList()){
QListWidgetItem *item = new QListWidgetItem(QIcon(finfo.absoluteFilePath()), finfo.fileName());
listWidget_images->addItem(item);
}
});