Auto create labels using GTK from Struct

I have this struct

struct ViewData {
    int ID;
    std::string Name;
    std::string Mode;
    std::string Status;
    std::string Type;
};

For some reason this function is not working at all, why? I will receive 3 sets of data in that struct generally. Ideally it would display all the labels in a series. But it is not drawing. Not even throwing an error or assertion warning.

for (std::size_t i = 0; i < parsedData.size(); ++i) {
    const ViewData& data = parsedData[i];
    // Create widgets for ID, Name, Mode, Status, and Type
    std::cout << "\nProcessing data ID: " << data.ID << std::endl;

    Gtk::Label idLabelWidget, nameLabelWidget, modeLabelWidget, statusLabelWidget, typeLabelWidget;
    Gtk::Label idValueLabelWidget, nameValueLabelWidget, modeValueLabelWidget, statusValueLabelWidget, typeValueLabelWidget;

    cout << "Label Creation at: " << data.ID;

    idLabelWidget.set_text("ID:");
    nameLabelWidget.set_text("Name:");
    modeLabelWidget.set_text("Mode:");
    statusLabelWidget.set_text("Status:");
    typeLabelWidget.set_text("Type:");

    cout << "Label Names at: " << data.ID;

    idValueLabelWidget.set_label(std::to_string(data.ID));
    nameValueLabelWidget.set_label(data.Name);
    modeValueLabelWidget.set_label(data.Mode);
    statusValueLabelWidget.set_label(data.Status);
    typeValueLabelWidget.set_label(data.Type);

    cout << "Label Values at: " << data.ID;
    // Add labels to the grid
    grid.attach(idLabelWidget,          0, row, 1, 1);
    grid.attach(idValueLabelWidget,     1, row, 1, 1);
    idLabelWidget.show(); 
    idValueLabelWidget.show();
    cout << "ID SET at: " << data.ID;

    grid.attach(nameLabelWidget,        2, row, 1, 1);
    grid.attach(nameValueLabelWidget,   3, row, 1, 1);
    cout << "NAME SET at: " << data.ID;

    grid.attach(modeLabelWidget,        4, row, 1, 1);
    grid.attach(modeValueLabelWidget,   5, row, 1, 1);
    cout << "MODE SET at: " << data.ID;

    grid.attach(statusLabelWidget,      6, row, 1, 1);
    grid.attach(statusValueLabelWidget, 7, row, 1, 1);
    cout << "STATUS SET at: " << data.ID;

    grid.attach(typeLabelWidget,        8, row, 1, 1);
    grid.attach(typeValueLabelWidget,   9, row, 1, 1);
    cout << "TYPE SET at: " << data.ID << endl;
    //box.pack_start(grid, Gtk::PACK_SHRINK); // Add grid to box
    cout << "************************************ at: " << data.ID << endl << std::flush;
    row += 2; // Increment row for next set of widgets
}

Tried Gtk::Label outside the loop. One of them printed, the second out of 3 elements. Then it threw assertion error for grid.attach. Tried pushing the row down multiple lines. Same error.

From the code you have show, I suspect your problem to be related to scope. Here is a simplified version of your code:

for (std::size_t i = 0; i < parsedData.size(); ++i)
{
    // Creating:
    Gtk::Label idLabelWidget, nameLabelWidget, modeLabelWidget, statusLabelWidget, typeLabelWidget;
    Gtk::Label idValueLabelWidget, nameValueLabelWidget, modeValueLabelWidget, statusValueLabelWidget, typeValueLabelWidget;

    // Attaching:
    grid.attach(idLabelWidget,          0, row, 1, 1);
    grid.attach(idValueLabelWidget,     1, row, 1, 1);
    grid.attach(nameLabelWidget,        2, row, 1, 1);
    grid.attach(nameValueLabelWidget,   3, row, 1, 1);
    grid.attach(modeLabelWidget,        4, row, 1, 1);
    grid.attach(modeValueLabelWidget,   5, row, 1, 1);
    grid.attach(statusLabelWidget,      6, row, 1, 1);
    grid.attach(statusValueLabelWidget, 7, row, 1, 1);
    grid.attach(typeLabelWidget,        8, row, 1, 1);
    grid.attach(typeValueLabelWidget,   9, row, 1, 1);

} // End of scope: labels destroyed.

On each iteration of the loop, the labels your declared inside de scope are destroyed. The Gtk::Grid::attach call takes a reference to the widget that it attaches. This means you are left with a dangling reference.

You should try moving the label creation outside of the loop.