signal printing to terminal

[Jamie Lahowetz <deadpickle gmail com>]

This is probably a fairly easy question but Im very new to c++ and gtkmm
 and am trying to connect a signal to a glade created entry. when return
 is pressed the text is grabbed from the entry and displays in the 
terminal... only nothing happens. A little help would be nice as to what
 im doing wrong. Thank you.

main.cpp:
#include <gtkmm.h>
#include <iostream>
#include "terminal.h"

int main(int argc, char *argv[])
{
//    required to start application methods
    Gtk::Main kit(argc, argv);


    Gtk::Window *mainwindow;

    //Load the GtkBuilder file
    Glib::RefPtr<Gtk::Builder> refBuilder = Gtk::Builder::create();
    try
    {
        refBuilder->add_from_file("

hprcc.glade");
    }
    catch(const Glib::FileError& ex)
    {
        std::cerr << "FileError: " << ex.what() << std::endl;
        return 1;
    }
    catch(const Glib::MarkupError& ex)
    {
        std::cerr << "MarkupError: " << ex.what() << std::endl;
        return 1;
    }
    catch(const Gtk::BuilderError& ex)
    {
        std::cerr << "BuilderError: " << ex.what() << std::endl;
        return 1;
    }

//    get the main window widget
    refBuilder->get_widget("mainwindow", mainwindow);

//    start the event loop
    kit.run(*mainwindow);

    return 0;
}


terminal.cpp:
#include "terminal.h"
#include <iostream>

using namespace std;

MainWindow::MainWindow(BaseObjectType* base_object,const Glib::RefPtr<Gtk::Builder>& glade_widget) : Gtk::Window(base_object)
{
//    widgets from Glade
    glade_widget->get_widget("stnidentry", stnidentry);

//    Signals
    stnidentry->signal_activate().connect(sigc::mem_fun(*this, &MainWindow::get_stn_info));
}

MainWindow::~MainWindow()
{
}

void MainWindow::get_stn_info()
{
    Glib::ustring stnid;

    stnid = stnidentry->get_text();
    std::cout << stnid << std::endl;
}


terminal.h:
#ifndef TERMINAL_H
#define TERMINAL_H

#include <gtkmm.h>

class MainWindow : public Gtk::Window
{
    public:
    MainWindow(BaseObjectType* cobject, const Glib::RefPtr<Gtk::Builder>& glade_widget);
    virtual ~MainWindow();

    protected:
//    custom callbacks
    void get_stn_info();

//    widgets from Glade
    Gtk::Entry* stnidentry;
};

#endif // TERMINAL_H