如何保持字典顺序？ [英] How to keep a Dictionary ordered?

问题描述

我有一个 Dictionary< string，Func< string，string>> 。我使用键来提供一个下拉菜单项，该菜单项允许用户选择要运行的算法。然后，我可以方便地将所选值反馈到字典中以获得相关功能。

I have a Dictionary<string, Func<string, string>>. I use the keys to provide the items of a drop-down which allows the user to select which algorithm to run. Then I can conveniently feed the selected value back into the dictionary to get the relevant function.

// Initialization
my_dict["Function #1"] = func1;
my_dict["Function #2"] = func2;

...

// Executing
result = my_dict[user_choice](input);

现在，当填充下拉列表时（ System.Windows.Forms。 ComboBox ）我用 foreach 遍历了这些键。 MSDN警告： System.Collections.Generic.Dictionary 不能保证顺序稳定。但实际上，我知道顺序非常稳定，因此现在可以使用。我确实希望这些功能能很好地为用户排序。

Now, when populating the drop down (a System.Windows.Forms.ComboBox) I loop through the keys of this with foreach. MSDN warns that System.Collections.Generic.Dictionary is not guaranteed to have a stable order. But in practice I know that the order is pretty stable, so it works for now. I do want the functions to be ordered nicely for the user.

但是，我想正确地执行此操作-即。通过使用保证订单稳定性的数据结构。不幸的是 OrderedDictionary 并没有帮助，因为它会强制将值设为 object s；我想让他们担任职能代表。同时，我不想增加太多不必要的复杂性（例如，我可以将键的副本存储为 List< string>

However, I want to do this correctly - ie. by using a data structure that guarantees order stability. Unfortunately OrderedDictionary is not helpful, since it forces the values to be objects; I'd like to keep them function delegates. At the same time, I don't want to add too much needless complexity (for instance, I could store a copy of the keys as a List<string> to use for order, but that seems like a poor solution).

我该怎么办？

注意： 似乎有些人认为我希望我的商品按字母顺序排列。我不。我希望它们保持与添加它们时的顺序相同。也就是说，如果在函数＃1之前添加键函数＃2

推荐答案

而不是使用 OrderedDictionary ，则应使用 SortedDictionary< TKey，TValue> 。

Instead of using the OrderedDictionary, you should use the SortedDictionary<TKey, TValue>.

此键按键排序。因此，以您的字符串为例。这样就足够了。

This one is sorted by the key. So for your example by your Strings. This should suffice.

如果您未使用任何本地可比较类型，则需要实现 IEqualityComparer< T> 键类的界面。

If you are not using any native comparable type you need to implement the IEqualityComparer<T> interface for your key-class.

这篇关于如何保持字典顺序？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！