(listtest:52278): Gtk-CRITICAL **: 10:31:28.256: gtk_container_add: assertion 'GTK_IS

抱歉，我之前给出的示例代码存在问题。在添加子控件时，需要将 gtk_container_add() 改为 gtk_container_add(GTK_CONTAINER(inner_box), child_item->child_listbox);。这样才能将子级列表框添加到父级项目中。

下面是修正后的示例代码：

#include <gtk/gtk.h>
typedef struct {
    gchar *label;
    GtkWidget *child_listbox;
} ListItem;
ListItem *list_item_new(const gchar *label) {
    ListItem *item = g_malloc(sizeof(ListItem));
    item->label = g_strdup(label);
    item->child_listbox = NULL;
    return item;
}
void list_item_free(ListItem *item) {
    if (item == NULL)
        return;
    
    g_free(item->label);
    if (GTK_IS_WIDGET(item->child_listbox))
        gtk_widget_destroy(item->child_listbox);
    g_free(item);
}
void add_child_item(GtkListBoxRow *parent_row, ListItem *child_item) {
    GtkWidget *inner_box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
    GtkWidget *label = gtk_label_new(child_item->label);
    gtk_container_add(GTK_CONTAINER(inner_box), label);
    if (GTK_IS_WIDGET(child_item->child_listbox))
        gtk_container_add(GTK_CONTAINER(inner_box), child_item->child_listbox);
	gtk_widget_show_all(inner_box); // 显示内部容器及其内容
	GtkWidget *row = gtk_list_box_row_new();
	gtk_container_add(GTK_CONTAINER(row), inner_box);
	gtk_widget_show(row); // 显示行控件
	gtk_list_box_insert(GTK_LIST_BOX(parent_row), row, -1); // 将行插入父级列表框
}
int main(int argc, char *argv[]) {
	gtk_init(&argc, &argv);
	GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
	gtk_window_set_title(GTK_WINDOW(window), "Multi-level List Demo");
	gtk_window_set_default_size(GTK_WINDOW(window), 400, 300);
	gtk_container_set_border_width(GTK_CONTAINER(window), 10);
	GtkWidget *box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
	gtk_container_add(GTK_CONTAINER(window), box);
	GtkWidget *listbox = gtk_list_box_new();
	gtk_box_pack_start(GTK_BOX(box), listbox, TRUE, TRUE, 0);
	ListItem *item1 = list_item_new("Item 1");
	GtkWidget *row1 = gtk_list_box_row_new();
	add_child_item(GTK_LIST_BOX_ROW(row1), item1);
	gtk_list_box_insert(GTK_LIST_BOX(listbox), row1, -1);
	ListItem *item2 = list_item_new("Subitem 1");
	item2->child_listbox = gtk_list_box_new();
	GtkWidget *row2 = gtk_list_box_row_new();
	add_child_item(GTK_LIST_BOX_ROW(row2), item2);
	gtk_container_add(GTK_CONTAINER(item1->child_listbox), row2);
    // 显示所有部件
    gtk_widget_show_all(window);
    // 进入主循环
    gtk_main();
    // 清理资源
	list_item_free(item1);  
	list_item_free(item2);  
	return 0;
}