将列表分配给另一个列表按值而不是引用

好的，所以我有从数据库中提取的列表 list1，我想暂时将其保存到列表 list2，对我的列表 1 执行一些操作，将其保存到数据库，然后使用 list2 并将其保存到数据库。问题是，因为一旦我更改 list1 中的某些字段，它就会通过引用传递，因此 list2 已经更新。

有没有办法将整个列表作为值而不是引用传递？

这里有一些代码可以更清楚地说明：

var CurrentMenuItems = dbContext.menu_items.Where(m => m.optgroup == currentGroup && m.day_id == menuItem.day_id).ToList();
           List<menu_item> MenuItemsToBeEditedAfterSubmitChanges = CurrentMenuItems;// we need to store this by value, so we can update it later

            byte ItemIncrease = 50; // To store temp value so we can avoid duplicate entry for item number 
            foreach (var item in CurrentMenuItems)
            {
                item.optgroup = nextGroup;
                item.item = ItemIncrease;
                ItemIncrease++; 
            }
            var menuItemsToBeReplaced = dbContext.menu_items.Where(m => m.optgroup == nextGroup && m.day_id == menuItem.day_id).ToList(); // we want to move all items within this group
            dbContext.SubmitChanges();
            foreach (var item in menuItemsToBeReplaced)
            {
                item.optgroup = currentGroup;
                item.item = (byte)(item.item - 1);
            }
            dbContext.SubmitChanges();
            // After first save, update the first group of menu items
            foreach (var item in MenuItemsToBeEditedAfterSubmitChanges)
            {
                item.optgroup = nextGroup;
                item.item = (byte)(item.item + 1);
            }
            dbContext.SubmitChanges();

List<int> originalList = new List<int>() { 0, 1, 2 };
List<int> copiedList = new List<int>(originalList);
copiedList[2] = 3; // originalList[2] still is 2

IList<string> f = new List<string>();
var t = f.ToList();

List<object> list2 = new List<object>(list1);