解决 找到多个具有相同 ID“_header”的控件,FindControl 要求控件具有唯一的 ID.

private void DisplayHotBooks()
    {
        //获取所有的书分类信息
        IList<Category> list = CategoryManager.GetAllCategories();
        int i = 0;
        foreach (Category item in list)
        {
            AccordionPane ap = new AccordionPane();
            Label lbMenu = new Label();
            lbMenu.Text = item.Name;
            ap.HeaderContainer.Controls.Add(lbMenu);
            Accordion1.Panes.Add(ap);
        }
    }

从异常"_header"可以猜测到与pane的header有关；于是手动添加不重复id

private void DisplayHotBooks()
    {
        //获取所有的书分类信息
        IList<Category> list = CategoryManager.GetAllCategories();
        int i = 0;
        foreach (Category item in list)
        {
            AccordionPane ap = new AccordionPane();
            Label lbMenu = new Label();
            lbMenu.Text = item.Name;
            ap.HeaderContainer.Controls.Add(lbMenu);
            ap.HeaderContainer.ID = "_header" + item.Id;
            Accordion1.Panes.Add(ap);
        }
    }

接着抛出异常 找到多个具有相同 ID“_content”的控件。FindControl 要求控件具有唯一的 ID。呵呵，差点忘了pane除了header还有content,于是再手动添加content id；最终如下：

private void DisplayHotBooks()
    {
        //获取所有的书分类信息
        IList<Category> list = CategoryManager.GetAllCategories();
        int i = 0;
        foreach (Category item in list)
        {
            AccordionPane ap = new AccordionPane();
            Label lbMenu = new Label();
            lbMenu.Text = item.Name;
            ap.HeaderContainer.Controls.Add(lbMenu);
            ap.HeaderContainer.ID = "_header" + item.Id;
            ap.ContentContainer.ID = "_content" + item.Id;
            Accordion1.Panes.Add(ap);
        }
    }