使用属性visible = false不会隐藏GtkLabel

Question

我正在尝试使用GTK在vala中创建一个Calendar Widget。我有一个其构造函数用42个标签填充Gtk.Grid的类。但是，当调用负责迭代标签列表的方法fill_grid_days（）时（根据最大天数隐藏或显示标签）首次运行时，直到在外部类中使用相同方法时，才隐藏标签按下按钮即可填充fill_grid_days（）。

CalendarView类-构造函数

public CalendarView () {
        this.orientation = Gtk.Orientation.VERTICAL;
        int max_labels = 42;
        var days_header = new DaysRow();

        /*
         * Grid that contains any number of days
         * day_of_week is the start day(m,t,w,t,f,s,s) of month
         * end_day is the final number day
         */
        day_grid = new Grid ();

        var col = 0;
        var row = 0;

        for (int i = 0; i < max_labels; i++) {
            var label_day = new Label("");
            label_day.get_style_context ().add_class ("label-day");
            label_day.expand = true;
            label_day.halign = Align.CENTER;
            label_day.valign = Align.START;

            day_grid.attach (label_day, col, row, 1, 1);
            col++;
            if (col != 0 && col % 7 == 0) {
                row++;
                col = 0;
            }
            labels.append(label_day);
        }

        this.pack_start (days_header);
        this.pack_end (day_grid);
    }

CalendarView类-fill_grid_days方法

public void fill_grid_days (int start_day, int max_day, int current_day) {
        /*
         * All days in interation to add a new Label
         */
        var day_number = 1;

        for (int i = 0; i < 42; i++) {
            Label label = labels.nth_data (i);
            label.get_style_context ().remove_class ("label-today");
            label.visible = true;
            /*
             * max_day + start_day, it is necessary to 
             * find the correct label in list
             */
            if (i < start_day || i >= max_day + start_day) {
                print ("\nMe pongo invisible");
                label.visible = false;
            } else {

                /*
                 * current_day + start_day, it is necessary to 
                 * find the correct label in list
                 */
                if ( current_day != -1 && (i+1) == current_day + start_day ) {
                    label.get_style_context ().add_class ("label-today");
                }
                //label.set_label (day_number.to_string());
                label.label = day_number.to_string();
                day_number++;
            }
        }
    }

完整代码 https://github.com/calo001/luna/blob/master/src/views/CalendarView.vala