QTableView only displays all data when scrolling down

christian20052

Hi,
I am building a custom database/tableviewer-program. I use QTableView to display the data and I am facing the following issue: When I initially load the table, only 256 rows are depicted although the table has more than 12000 rows. As I scroll down however, these rows get "dynamically added" as you can see in this sequence of pictures (note the row number and scroll bar height):

Scrolling back up:

I already figured out that it is the underlying model which is missing the rows, however, I don't know how to properly update it.
My code for the constructor:

TableTab::TableTab(QString tablename_sql, QString time_lower_bound, QString time_upper_bound, QString filepath_prefix) : QWidget(){

    model = new QSqlTableModel(this);

    createTable(tablename_sql, time_lower_bound, filepath_prefix);
    addDataToTableByTime(tablename_sql, time_lower_bound, time_upper_bound, filepath_prefix);

    index_current_x_axis = -1;
    index_current_y_axis = -1;

    model->setTable(tablename_sql);
    model->select();

    QAction *action_ctrlc = new QAction(this);
    this->addAction(action_ctrlc);
    action_ctrlc->setShortcut(QKeySequence("Ctrl+C"));

    connect(action_ctrlc, &QAction::triggered, this, &TableTab::copy_button_clicked);

    mytableview = new QTableView;
    mytableview->setModel(model);
    mytableview->show();
    mytableview->setEditTriggers(QAbstractItemView::NoEditTriggers);

    this->setContextMenuPolicy(Qt::CustomContextMenu);
    mytableview->setContextMenuPolicy(Qt::CustomContextMenu);
    mytableview->horizontalHeader()->setContextMenuPolicy(Qt::CustomContextMenu);

    connect(mytableview, &QTableView::customContextMenuRequested, this, &TableTab::ShowContextMenuCopy);
    connect(mytableview->horizontalHeader(), &QHeaderView::customContextMenuRequested, this, &TableTab::ShowContextMenuCopy);



    QPushButton *plot_button = new QPushButton("Plot x-y data");
    connect(plot_button, &QPushButton::clicked, this, &TableTab::plotSelectedData);

    QLabel *label_export = new QLabel("Filepath including file extension:");
    checkbox_header = new QCheckBox();
    checkbox_header->setText("Include column names as header when exporting or pressing Ctrl+C");
    lineedit_export = new QLineEdit("");

    QPushButton *export_button = new QPushButton("Export selection");
    connect(export_button, &QPushButton::clicked, this, &TableTab::exportSelection);

    QGridLayout *mainLayout = new QGridLayout;
    mainLayout->addWidget(mytableview,0,0,1,2);
    mainLayout->addWidget(plot_button,1,0);
    mainLayout->addWidget(label_export,2,0);
    mainLayout->addWidget(checkbox_header,2,1);
    mainLayout->addWidget(lineedit_export,3,0);
    mainLayout->addWidget(export_button,3,1);

    mainLayout->setVerticalSpacing(20);
    setLayout(mainLayout);

}

What might be wrong?

Christian Ehrlicher

See for instance here

christian20052

Thanks, that solved it. I just didn't know what to search for.