Here is the code..
                    Glib::RefPtr<Gio::File> file = Gio::File::create_for_path(filepath);
Gtk::AppChooserDialog *dialog = new Gtk::AppChooserDialog(file, *this);
if ( dialog->run() == Gtk::RESPONSE_OK ) {
    Glib::RefPtr<Gio::AppInfo> appinfo = dialog->get_app_info();
    appinfo->launch(file);
}
dialog->hide();
                    This is the message i get when the above code is
                      executed..
                    glibmm-WARNING **: Glib::ConstructParams::ConstructParams(): object class "gtkmm__GtkAppChooserDialog" has no property named "file"
                    I'm probably making a silly mistake here. Can
                      anyone help me with this? Thanks in advance..