C#中的双向字典/地图

Dictionary<string, int> biDictionary = new Dictionary<string, int>();

biDictionary.Add("one", 1);
biDictionary.Add("two", 2);
biDictionary.Add("three", 3);

biDictionary["four"] = 4;
int value = biDictionary["two"];

Dictionary<string, int> forwardDictionary = new Dictionary<string, int>();
Dictionary<int, string> reverseDictionary = new Dictionary<int, string>();

forwardDictionary.Add("one", 1);
reverseDictionary.Add(1, "one");

forwardDictionary.Add("two", 2);
reverseDictionary.Add(2, "two");

forwardDictionary.Add("three", 3);
reverseDictionary.Add(3, "three");