C# 如何设计在编译时以未知顺序遍历多个列表的算法？

我正在创建一个程序，它根据用户定义的设置处理数据。 在处理过程中，我有一些相关的列表，必须根据这些用户定义的设置进行迭代；用户决定这些列表的迭代顺序

我想知道如何设计一种算法来迭代这些列表，同时仍然有非常可维护的代码。这里的想法不是以一个函数结束，该函数有一个巨大的切换案例，其中每个案例都对一个列表进行迭代

示例：
假设我需要处理的数据是不同类型食物的列表。 用户必须指定不同食物组的加工顺序。食品组只是存储各种食品的列表：

List<string> grains = new List<string> { "Bread", "Pasta", "Cereal", "Rice" };
List<string> vegetables = new List<string> { "Corn", "Pea", "Carrot", "Tomato" };
List<string> fruits = new List<string> { "Apple", "Orange", "Banana", "Pear" };
List<string> meat = new List<string> { "Beef", "Chicken", "Pork", "Turkey" };
List<string> diary = new List<string> { "Milk", "Cheese", "Yogurt", "Cream" };

在我的应用程序中，case语句实际上包含的代码比示例中简单的foreach循环多得多。有没有更好的方法来设计这个算法？虽然没有必要，但我想知道是否也有一种可扩展的方法来设计这样的算法（添加/删除新食物组不会破坏算法）。

将其作为字典：

Dictionary<string, List<string>> lists = new Dictionary<string, List<string>>();
lists["grains"] = new List<string> { "Bread", "Pasta", "Cereal", "Rice" };
lists["vegetables"] = new List<string> { "Corn", "Pea", "Carrot", "Tomato" };
lists["fruits"] = new List<string> { "Apple", "Orange", "Banana", "Pear" };
lists["meat"] = new List<string> { "Beef", "Chicken", "Pork", "Turkey" };
lists["diary"] = new List<string> { "Milk", "Cheese", "Yogurt", "Cream" };

---

实际上，C#中还有一些更好的语法用于初始化。请参阅：

描述您要查找的代码的术语是“数据驱动”。

foreach(string foodGroup in order)
{
    switch(foodGroup)
    {
        case "grains":
            foreach(string foodItem in grains)
            {
                ProcessFood(foodItem);
            }
            break;
        case "vegetables":
            foreach(string foodItem in vegetables)
            {
                ProcessFood(foodItem);
            }
            break;
        case "fruits":
            foreach(string foodItem in fruits)
            {
                ProcessFood(foodItem);
            }
            break;
        case "meat":
            foreach(string foodItem in meat)
            {
                ProcessFood(foodItem);
            }
            break;
        case "diary":
            foreach(string foodItem in diary)
            {
                ProcessFood(foodItem);
            }
            break;
    }
}

Dictionary<string, List<string>> lists = new Dictionary<string, List<string>>();
lists["grains"] = new List<string> { "Bread", "Pasta", "Cereal", "Rice" };
lists["vegetables"] = new List<string> { "Corn", "Pea", "Carrot", "Tomato" };
lists["fruits"] = new List<string> { "Apple", "Orange", "Banana", "Pear" };
lists["meat"] = new List<string> { "Beef", "Chicken", "Pork", "Turkey" };
lists["diary"] = new List<string> { "Milk", "Cheese", "Yogurt", "Cream" };

foreach(string foodGroup in order)
{
   foreach(string foodItem in lists[foodGroup])
   {
      ProcessFood(foodItem);
   }
}