winform窗体中遍历当前页面全部控件并赋值

winform窗体中遍历当前页面所有控件并赋值
麻烦各位大神给看下下面的代码，那里出错了，遍历当前页面所有控件。窗体里面有groupBox以及panel

private void BcforLoading(Control container)
        {
            foreach (Control com in container.Controls)
            {
                if (com.HasChildren)
                {
                    BcforLoading(com);
                }
                if (com.Name.Substring(com.Name.Length - 4, 4) == "_JCZ" && com is ComboBox)
                {
                    ComboBox cb = (ComboBox)com;
                    cb.Items.Add(UserContext.LoggedUser);
                    cb.SelectedItem = UserContext.LoggedUser;
                }
                if (com.Name.Substring(com.Name.Length - 3, 3) == "_BZ" && com is ComboBox)
                {
                    ComboBox cb = (ComboBox)com;
                    cb.SelectedValue = UserContext.LoggedUserTeam;
                }
                if (com.Name.Substring(com.Name.Length - 3, 3) == "_BC" && com is ComboBox)
                {
                    ComboBox cb = (ComboBox)com;
                    cb.SelectedValue = UserContext.LoggedUserSort;
                }
            }
        }
------解决思路----------------------
这错误应该是Substring(com.Name.Length - 4, 4)，因为如果com.Name的长度小于4，那么你执行的其实就是Substring(-1, 4)，所以报错了，你要预先判断一下长度
------解决思路----------------------
吧条件表达式调一下位置
 if (com.Name.Substring(com.Name.Length - 4, 4) == "_JCZ" && com is ComboBox)
改为
 if (com is ComboBox && com.Name.Substring(com.Name.Length - 4, 4) == "_JCZ")