How to work with menu items dynamically

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C#3.5

I got some menus in my application built using

<asp:Menu>

In that, I got STYLES as default and under STYLES, I need to load sub menus like this?

STYLES
1
2

The code I used to load the submenu:

MenuItem root = new MenuItem("STYLES");
            for(int i=0;i<dt.Tables[0].Rows.Count;i++)
            {
                root.ChildItems.Add(new MenuItem(dt.Tables[0].Rows[i]["Season"].ToString()));
            }

But this code is not working.. The submenus are not loaded. What would be the error ???