Close main window ffrom messagebox using gtkmm / c++

Question

From a message box i'd like to close the main window if i click on Ok button.

class usb_boot : public Gtk::Window{

public:
    usb_boot();

and from message box

i tried this

void usb_boot::creation(){
//Gtk::MessageDialog dialog(*this, dropdownList.get_active_text());
std::string message("Format : " + type);
Gtk::MessageDialog *dialog = new Gtk::MessageDialog("Resume", true, Gtk::MESSAGE_QUESTION, Gtk::BUTTONS_YES_NO);
dialog->set_title("Resume");
dialog->set_message(dropdownList.get_active_text());
dialog->set_secondary_text(message);
dialog->set_default_response(Gtk::RESPONSE_YES);
int result = dialog->run();

switch(result){

    case(Gtk::RESPONSE_YES):{

        std::cout << "next program" << std::endl;
        delete dialog;// ok work
        usb_boot().close();//compile but doesn't close main window
        break;
    }

How to close the main window ?

Answer 1

You should avoid using raw new/delete whenever you can (like here, for instance). For message dialogs, you can use simple scopes:

#include <iostream>
#include <gtkmm.h>

class MainWindow : public Gtk::ApplicationWindow
{

public:
    MainWindow() = default;

};

int main(int argc, char **argv)
{
    auto app = Gtk::Application::create(argc, argv, "so.question.q63872817");
    
    MainWindow w;
    w.show_all();
    
    int result;
    // Here we put the dialog inside a scope so that it is destroyed
    // automatically when the user makes a choice (you could do it
    // inside a function instead of a free scope):
    {
        Gtk::MessageDialog dialog(w, "Message dialog", true, Gtk::MESSAGE_QUESTION, Gtk::BUTTONS_YES_NO);
        dialog.set_title("Title");
        dialog.set_message("Primary message");
        dialog.set_secondary_text("Secondary message");
        dialog.set_default_response(Gtk::RESPONSE_YES);
        
        result = dialog.run();
        
    } // Here the dialog is destroyed and closed.
    
    if(result == Gtk::RESPONSE_YES)
    {
        std::cout << "Closing main window..." << std::endl;
        //MainWindow().close(); // Will not work!
        w.close();
    }

    return app->run(w);
}

Also, in your code, you call usb_boot().close(), but notice the extra parenthesis after usb_boot. This constructs a new usb_boot object (since you call the constructor) and immediately closes it. In the example above, I called w.close(), instead of MainWindow().close().