I am looking for a generic, bidirectional 1 to 1 Dictionary class in C# (2), ie. a BiDictionaryOneToOne<T, S> which is guaranteed to only contain one of each value and key (up to RefEquals anyway), and which can be searched using either key or value. Anyone know of one, or should I just implement it myself? I can't believe that I'm the first person to need this...
我正在寻找C#(2)中的通用双向1到1字典类,即。 BiDictionaryOneToOne
There is a BiDictionary in the answers to this question, but it is not for unique elements (and also does not implement RemoveByFirst(T t) or RemoveBySecond(S s)).
在这个问题的答案中有一个BiDictionary,但它不适用于唯一元素(并且也不实现RemoveByFirst(T t)或RemoveBySecond(S s))。
Thanks!
7 个解决方案
#1
67
OK, here is my attempt (building on Jon's - thanks), archived here and open for improvement :
好的,这是我的尝试(建立在Jon的 - 感谢),存档在这里并开放改进:
/// <summary>/// This is a dictionary guaranteed to have only one of each value and key. /// It may be searched either by TFirst or by TSecond, giving a unique answer because it is 1 to 1./// </summary>/// <typeparam name="TFirst">The type of the "key"</typeparam>/// <typeparam name="TSecond">The type of the "value"</typeparam>public class BiDictionaryOneToOne<TFirst, TSecond>{ IDictionary<TFirst, TSecond> firstToSecond = new Dictionary<TFirst, TSecond>(); IDictionary<TSecond, TFirst> secondToFirst = new Dictionary<TSecond, TFirst>(); #region Exception throwing methods /// <summary> /// Tries to add the pair to the dictionary. /// Throws an exception if either element is already in the dictionary /// </summary> /// <param name="first"></param> /// <param name="second"></param> public void Add(TFirst first, TSecond second) { if (firstToSecond.ContainsKey(first) || secondToFirst.ContainsKey(second)) throw new ArgumentException("Duplicate first or second"); firstToSecond.Add(first, second); secondToFirst.Add(second, first); } /// <summary> /// Find the TSecond corresponding to the TFirst first /// Throws an exception if first is not in the dictionary. /// </summary> /// <param name="first">the key to search for</param> /// <returns>the value corresponding to first</returns> public TSecond GetByFirst(TFirst first) { TSecond second; if (!firstToSecond.TryGetValue(first, out second)) throw new ArgumentException("first"); return second; } /// <summary> /// Find the TFirst corresponing to the Second second. /// Throws an exception if second is not in the dictionary. /// </summary> /// <param name="second">the key to search for</param> /// <returns>the value corresponding to second</returns> public TFirst GetBySecond(TSecond second) { TFirst first; if (!secondToFirst.TryGetValue(second, out first)) throw new ArgumentException("second"); return first; } /// <summary> /// Remove the record containing first. /// If first is not in the dictionary, throws an Exception. /// </summary> /// <param name="first">the key of the record to delete</param> public void RemoveByFirst(TFirst first) { TSecond second; if (!firstToSecond.TryGetValue(first, out second)) throw new ArgumentException("first"); firstToSecond.Remove(first); secondToFirst.Remove(second); } /// <summary> /// Remove the record containing second. /// If second is not in the dictionary, throws an Exception. /// </summary> /// <param name="second">the key of the record to delete</param> public void RemoveBySecond(TSecond second) { TFirst first; if (!secondToFirst.TryGetValue(second, out first)) throw new ArgumentException("second"); secondToFirst.Remove(second); firstToSecond.Remove(first); } #endregion #region Try methods /// <summary> /// Tries to add the pair to the dictionary. /// Returns false if either element is already in the dictionary /// </summary> /// <param name="first"></param> /// <param name="second"></param> /// <returns>true if successfully added, false if either element are already in the dictionary</returns> public Boolean TryAdd(TFirst first, TSecond second) { if (firstToSecond.ContainsKey(first) || secondToFirst.ContainsKey(second)) return false; firstToSecond.Add(first, second); secondToFirst.Add(second, first); return true; } /// <summary> /// Find the TSecond corresponding to the TFirst first. /// Returns false if first is not in the dictionary. /// </summary> /// <param name="first">the key to search for</param> /// <param name="second">the corresponding value</param> /// <returns>true if first is in the dictionary, false otherwise</returns> public Boolean TryGetByFirst(TFirst first, out TSecond second) { return firstToSecond.TryGetValue(first, out second); } /// <summary> /// Find the TFirst corresponding to the TSecond second. /// Returns false if second is not in the dictionary. /// </summary> /// <param name="second">the key to search for</param> /// <param name="first">the corresponding value</param> /// <returns>true if second is in the dictionary, false otherwise</returns> public Boolean TryGetBySecond(TSecond second, out TFirst first) { return secondToFirst.TryGetValue(second, out first); } /// <summary> /// Remove the record containing first, if there is one. /// </summary> /// <param name="first"></param> /// <returns> If first is not in the dictionary, returns false, otherwise true</returns> public Boolean TryRemoveByFirst(TFirst first) { TSecond second; if (!firstToSecond.TryGetValue(first, out second)) return false; firstToSecond.Remove(first); secondToFirst.Remove(second); return true; } /// <summary> /// Remove the record containing second, if there is one. /// </summary> /// <param name="second"></param> /// <returns> If second is not in the dictionary, returns false, otherwise true</returns> public Boolean TryRemoveBySecond(TSecond second) { TFirst first; if (!secondToFirst.TryGetValue(second, out first)) return false; secondToFirst.Remove(second); firstToSecond.Remove(first); return true; } #endregion /// <summary> /// The number of pairs stored in the dictionary /// </summary> public Int32 Count { get { return firstToSecond.Count; } } /// <summary> /// Removes all items from the dictionary. /// </summary> public void Clear() { firstToSecond.Clear(); secondToFirst.Clear(); }}#2
16
A more complete implementation of bidirectional dictionary:
双向字典的更完整实现:
-
Supports almost all interfaces of original
Dictionary<TKey,TValue>(except infrastructure interfaces):IDictionary<TKey, TValue>IReadOnlyDictionary<TKey, TValue>IDictionary-
ICollection<KeyValuePair<TKey, TValue>>(this one and below are the base interfaces of the ones above) ICollectionIReadOnlyCollection<KeyValuePair<TKey, TValue>>IEnumerable<KeyValuePair<TKey, TValue>>IEnumerable
ICollection
>(这一个及以下是以上的基本接口) -
Serialization using
SerializableAttribute. -
Debug view using
DebuggerDisplayAttribute(with Count info) andDebuggerTypeProxyAttribute(for displaying key-value pairs in watches). - Reverse dictionary is available as
IDictionary<TValue, TKey> Reverseproperty and also implements all interfaces mentioned above. All operations on either dictionaries modify both.
支持原始Dictionary
使用SerializableAttribute进行序列化。
使用DebuggerDisplayAttribute(带有Count信息)和DebuggerTypeProxyAttribute(用于在watch中显示键值对)的Debug视图。
反向字典可用作IDictionary
Usage:
var dic = new BiDictionary<int, string>();dic.Add(1, "1");dic[2] = "2";dic.Reverse.Add("3", 3);dic.Reverse["4"] = 4;dic.Clear();Code is available in my private framework on GitHub: BiDictionary(TFirst,TSecond).cs (permalink, search).
代码可以在GitHub的私有框架中找到:BiDictionary(TFirst,TSecond).cs(永久链接,搜索)。
Copy:
[Serializable][DebuggerDisplay ("Count = {Count}"), DebuggerTypeProxy (typeof(DictionaryDebugView<,>))]public class BiDictionary<TFirst, TSecond> : IDictionary<TFirst, TSecond>, IReadOnlyDictionary<TFirst, TSecond>, IDictionary{ private readonly IDictionary<TFirst, TSecond> _firstToSecond = new Dictionary<TFirst, TSecond>(); [NonSerialized] private readonly IDictionary<TSecond, TFirst> _secondToFirst = new Dictionary<TSecond, TFirst>(); [NonSerialized] private readonly ReverseDictionary _reverseDictionary; public BiDictionary () { _reverseDictionary = new ReverseDictionary(this); } public IDictionary<TSecond, TFirst> Reverse { get { return _reverseDictionary; } } public int Count { get { return _firstToSecond.Count; } } object ICollection.SyncRoot { get { return ((ICollection)_firstToSecond).SyncRoot; } } bool ICollection.IsSynchronized { get { return ((ICollection)_firstToSecond).IsSynchronized; } } bool IDictionary.IsFixedSize { get { return ((IDictionary)_firstToSecond).IsFixedSize; } } public bool IsReadOnly { get { return _firstToSecond.IsReadOnly || _secondToFirst.IsReadOnly; } } public TSecond this [TFirst key] { get { return _firstToSecond[key]; } set { _firstToSecond[key] = value; _secondToFirst[value] = key; } } object IDictionary.this [object key] { get { return ((IDictionary)_firstToSecond)[key]; } set { ((IDictionary)_firstToSecond)[key] = value; ((IDictionary)_secondToFirst)[value] = key; } } public ICollection<TFirst> Keys { get { return _firstToSecond.Keys; } } ICollection IDictionary.Keys { get { return ((IDictionary)_firstToSecond).Keys; } } IEnumerable<TFirst> IReadOnlyDictionary<TFirst, TSecond>.Keys { get { return ((IReadOnlyDictionary<TFirst, TSecond>)_firstToSecond).Keys; } } public ICollection<TSecond> Values { get { return _firstToSecond.Values; } } ICollection IDictionary.Values { get { return ((IDictionary)_firstToSecond).Values; } } IEnumerable<TSecond> IReadOnlyDictionary<TFirst, TSecond>.Values { get { return ((IReadOnlyDictionary<TFirst, TSecond>)_firstToSecond).Values; } } public IEnumerator<KeyValuePair<TFirst, TSecond>> GetEnumerator () { return _firstToSecond.GetEnumerator(); } IEnumerator IEnumerable.GetEnumerator () { return GetEnumerator(); } IDictionaryEnumerator IDictionary.GetEnumerator () { return ((IDictionary)_firstToSecond).GetEnumerator(); } public void Add (TFirst key, TSecond value) { _firstToSecond.Add(key, value); _secondToFirst.Add(value, key); } void IDictionary.Add (object key, object value) { ((IDictionary)_firstToSecond).Add(key, value); ((IDictionary)_secondToFirst).Add(value, key); } public void Add (KeyValuePair<TFirst, TSecond> item) { _firstToSecond.Add(item); _secondToFirst.Add(item.Reverse()); } public bool ContainsKey (TFirst key) { return _firstToSecond.ContainsKey(key); } public bool Contains (KeyValuePair<TFirst, TSecond> item) { return _firstToSecond.Contains(item); } public bool TryGetValue (TFirst key, out TSecond value) { return _firstToSecond.TryGetValue(key, out value); } public bool Remove (TFirst key) { TSecond value; if (_firstToSecond.TryGetValue(key, out value)) { _firstToSecond.Remove(key); _secondToFirst.Remove(value); return true; } else return false; } void IDictionary.Remove (object key) { var firstToSecond = (IDictionary)_firstToSecond; if (!firstToSecond.Contains(key)) return; var value = firstToSecond[key]; firstToSecond.Remove(key); ((IDictionary)_secondToFirst).Remove(value); } public bool Remove (KeyValuePair<TFirst, TSecond> item) { return _firstToSecond.Remove(item); } public bool Contains (object key) { return ((IDictionary)_firstToSecond).Contains(key); } public void Clear () { _firstToSecond.Clear(); _secondToFirst.Clear(); } public void CopyTo (KeyValuePair<TFirst, TSecond>[] array, int arrayIndex) { _firstToSecond.CopyTo(array, arrayIndex); } void ICollection.CopyTo (Array array, int index) { ((IDictionary)_firstToSecond).CopyTo(array, index); } [OnDeserialized] internal void OnDeserialized (StreamingContext context) { _secondToFirst.Clear(); foreach (var item in _firstToSecond) _secondToFirst.Add(item.Value, item.Key); } private class ReverseDictionary : IDictionary<TSecond, TFirst>, IReadOnlyDictionary<TSecond, TFirst>, IDictionary { private readonly BiDictionary<TFirst, TSecond> _owner; public ReverseDictionary (BiDictionary<TFirst, TSecond> owner) { _owner = owner; } public int Count { get { return _owner._secondToFirst.Count; } } object ICollection.SyncRoot { get { return ((ICollection)_owner._secondToFirst).SyncRoot; } } bool ICollection.IsSynchronized { get { return ((ICollection)_owner._secondToFirst).IsSynchronized; } } bool IDictionary.IsFixedSize { get { return ((IDictionary)_owner._secondToFirst).IsFixedSize; } } public bool IsReadOnly { get { return _owner._secondToFirst.IsReadOnly || _owner._firstToSecond.IsReadOnly; } } public TFirst this [TSecond key] { get { return _owner._secondToFirst[key]; } set { _owner._secondToFirst[key] = value; _owner._firstToSecond[value] = key; } } object IDictionary.this [object key] { get { return ((IDictionary)_owner._secondToFirst)[key]; } set { ((IDictionary)_owner._secondToFirst)[key] = value; ((IDictionary)_owner._firstToSecond)[value] = key; } } public ICollection<TSecond> Keys { get { return _owner._secondToFirst.Keys; } } ICollection IDictionary.Keys { get { return ((IDictionary)_owner._secondToFirst).Keys; } } IEnumerable<TSecond> IReadOnlyDictionary<TSecond, TFirst>.Keys { get { return ((IReadOnlyDictionary<TSecond, TFirst>)_owner._secondToFirst).Keys; } } public ICollection<TFirst> Values { get { return _owner._secondToFirst.Values; } } ICollection IDictionary.Values { get { return ((IDictionary)_owner._secondToFirst).Values; } } IEnumerable<TFirst> IReadOnlyDictionary<TSecond, TFirst>.Values { get { return ((IReadOnlyDictionary<TSecond, TFirst>)_owner._secondToFirst).Values; } } public IEnumerator<KeyValuePair<TSecond, TFirst>> GetEnumerator () { return _owner._secondToFirst.GetEnumerator(); } IEnumerator IEnumerable.GetEnumerator () { return GetEnumerator(); } IDictionaryEnumerator IDictionary.GetEnumerator () { return ((IDictionary)_owner._secondToFirst).GetEnumerator(); } public void Add (TSecond key, TFirst value) { _owner._secondToFirst.Add(key, value); _owner._firstToSecond.Add(value, key); } void IDictionary.Add (object key, object value) { ((IDictionary)_owner._secondToFirst).Add(key, value); ((IDictionary)_owner._firstToSecond).Add(value, key); } public void Add (KeyValuePair<TSecond, TFirst> item) { _owner._secondToFirst.Add(item); _owner._firstToSecond.Add(item.Reverse()); } public bool ContainsKey (TSecond key) { return _owner._secondToFirst.ContainsKey(key); } public bool Contains (KeyValuePair<TSecond, TFirst> item) { return _owner._secondToFirst.Contains(item); } public bool TryGetValue (TSecond key, out TFirst value) { return _owner._secondToFirst.TryGetValue(key, out value); } public bool Remove (TSecond key) { TFirst value; if (_owner._secondToFirst.TryGetValue(key, out value)) { _owner._secondToFirst.Remove(key); _owner._firstToSecond.Remove(value); return true; } else return false; } void IDictionary.Remove (object key) { var firstToSecond = (IDictionary)_owner._secondToFirst; if (!firstToSecond.Contains(key)) return; var value = firstToSecond[key]; firstToSecond.Remove(key); ((IDictionary)_owner._firstToSecond).Remove(value); } public bool Remove (KeyValuePair<TSecond, TFirst> item) { return _owner._secondToFirst.Remove(item); } public bool Contains (object key) { return ((IDictionary)_owner._secondToFirst).Contains(key); } public void Clear () { _owner._secondToFirst.Clear(); _owner._firstToSecond.Clear(); } public void CopyTo (KeyValuePair<TSecond, TFirst>[] array, int arrayIndex) { _owner._secondToFirst.CopyTo(array, arrayIndex); } void ICollection.CopyTo (Array array, int index) { ((IDictionary)_owner._secondToFirst).CopyTo(array, index); } }}internal class DictionaryDebugView<TKey, TValue>{ private readonly IDictionary<TKey, TValue> _dictionary; [DebuggerBrowsable (DebuggerBrowsableState.RootHidden)] public KeyValuePair<TKey, TValue>[] Items { get { var array = new KeyValuePair<TKey, TValue>[_dictionary.Count]; _dictionary.CopyTo(array, 0); return array; } } public DictionaryDebugView (IDictionary<TKey, TValue> dictionary) { if (dictionary == null) throw new ArgumentNullException("dictionary"); _dictionary = dictionary; }}public static class KeyValuePairExts{ public static KeyValuePair<TValue, TKey> Reverse<TKey, TValue> (this KeyValuePair<TKey, TValue> @this) { return new KeyValuePair<TValue, TKey>(@this.Value, @this.Key); }}#3
11
The question you refer to also shows a one-to-one implementation in this answer. Adding RemoveByFirst and RemoveBySecond would be trivial - as would implementing extra interfaces etc.
您提到的问题还显示了此答案中的一对一实现。添加RemoveByFirst和RemoveBySecond将是微不足道的 - 正如实现额外的接口等。
#4
3
This is same as accepted answer, but I provided Update methods as well, and over all little more fleshed out:
这与已接受的答案相同,但我也提供了更新方法,并且更加充实了:
public class BiDictionary<TKey1, TKey2> : IEnumerable<Tuple<TKey1, TKey2>>{ Dictionary<TKey1, TKey2> _forwards; Dictionary<TKey2, TKey1> _reverses; public int Count { get { if (_forwards.Count != _reverses.Count) throw new Exception("somewhere logic went wrong and your data got corrupt"); return _forwards.Count; } } public ICollection<TKey1> Key1s { get { return _forwards.Keys; } } public ICollection<TKey2> Key2s { get { return _reverses.Keys; } } public BiDictionary(IEqualityComparer<TKey1> comparer1 = null, IEqualityComparer<TKey2> comparer2 = null) { _forwards = new Dictionary<TKey1, TKey2>(comparer1); _reverses = new Dictionary<TKey2, TKey1>(comparer2); } public bool ContainsKey1(TKey1 key) { return ContainsKey(key, _forwards); } private static bool ContainsKey<S, T>(S key, Dictionary<S, T> dict) { return dict.ContainsKey(key); } public bool ContainsKey2(TKey2 key) { return ContainsKey(key, _reverses); } public TKey2 GetValueByKey1(TKey1 key) { return GetValueByKey(key, _forwards); } private static T GetValueByKey<S, T>(S key, Dictionary<S, T> dict) { return dict[key]; } public TKey1 GetValueByKey2(TKey2 key) { return GetValueByKey(key, _reverses); } public bool TryGetValueByKey1(TKey1 key, out TKey2 value) { return TryGetValue(key, _forwards, out value); } private static bool TryGetValue<S, T>(S key, Dictionary<S, T> dict, out T value) { return dict.TryGetValue(key, out value); } public bool TryGetValueByKey2(TKey2 key, out TKey1 value) { return TryGetValue(key, _reverses, out value); } public bool Add(TKey1 key1, TKey2 key2) { if (ContainsKey1(key1) || ContainsKey2(key2)) // very important return false; AddOrUpdate(key1, key2); return true; } public void AddOrUpdateByKey1(TKey1 key1, TKey2 key2) { if (!UpdateByKey1(key1, key2)) AddOrUpdate(key1, key2); } // dont make this public; a dangerous method used cautiously in this class private void AddOrUpdate(TKey1 key1, TKey2 key2) { _forwards[key1] = key2; _reverses[key2] = key1; } public void AddOrUpdateKeyByKey2(TKey2 key2, TKey1 key1) { if (!UpdateByKey2(key2, key1)) AddOrUpdate(key1, key2); } public bool UpdateKey1(TKey1 oldKey, TKey1 newKey) { return UpdateKey(oldKey, _forwards, newKey, (key1, key2) => AddOrUpdate(key1, key2)); } private static bool UpdateKey<S, T>(S oldKey, Dictionary<S, T> dict, S newKey, Action<S, T> updater) { T otherKey; if (!TryGetValue(oldKey, dict, out otherKey) || ContainsKey(newKey, dict)) return false; Remove(oldKey, dict); updater(newKey, otherKey); return true; } public bool UpdateKey2(TKey2 oldKey, TKey2 newKey) { return UpdateKey(oldKey, _reverses, newKey, (key1, key2) => AddOrUpdate(key2, key1)); } public bool UpdateByKey1(TKey1 key1, TKey2 key2) { return UpdateByKey(key1, _forwards, _reverses, key2, (k1, k2) => AddOrUpdate(k1, k2)); } private static bool UpdateByKey<S, T>(S key1, Dictionary<S, T> forwards, Dictionary<T, S> reverses, T key2, Action<S, T> updater) { T otherKey; if (!TryGetValue(key1, forwards, out otherKey) || ContainsKey(key2, reverses)) return false; if (!Remove(otherKey, reverses)) throw new Exception("somewhere logic went wrong and your data got corrupt"); updater(key1, key2); return true; } public bool UpdateByKey2(TKey2 key2, TKey1 key1) { return UpdateByKey(key2, _reverses, _forwards, key1, (k1, k2) => AddOrUpdate(k2, k1)); } public bool RemoveByKey1(TKey1 key) { return RemoveByKey(key, _forwards, _reverses); } private static bool RemoveByKey<S, T>(S key, Dictionary<S, T> keyDict, Dictionary<T, S> valueDict) { T otherKey; if (!TryGetValue(key, keyDict, out otherKey)) return false; if (!Remove(key, keyDict) || !Remove(otherKey, valueDict)) throw new Exception("somewhere logic went wrong and your data got corrupt"); return true; } private static bool Remove<S, T>(S key, Dictionary<S, T> dict) { return dict.Remove(key); } public bool RemoveByKey2(TKey2 key) { return RemoveByKey(key, _reverses, _forwards); } public void Clear() { _forwards.Clear(); _reverses.Clear(); } public IEnumerator<Tuple<TKey1, TKey2>> GetEnumerator() { if (_forwards.Count != _reverses.Count) throw new Exception("somewhere logic went wrong and your data got corrupt"); foreach (var item in _forwards) yield return Tuple.Create(item.Key, item.Value); } IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); }}Similar to my answer here
与我的答案类似
Few things to note:
几点注意事项:
-
I have implemented only
IEnumerable<>. I don't thinkICollection<>makes sense here since the method names all could be way different for this special collection structure. Up to you to decide what should go insideIEnumerable<>. So now you have collection initializer syntax too, like我只实现了IEnumerable <>。我不认为ICollection <>在这里有意义,因为这个特殊的集合结构的方法名称都可能有所不同。由您决定IEnumerable <>内应该包含哪些内容。所以现在你也有了集合初始化器语法,比如
var p = new BiDictionary<int, string> { 1, "a" }, { 2, "b" } }; -
I have attempted for some weird exceptions to be thrown here and there - just for data integrity. Just to be on the safer side so that you know if ever my code has bugs.
我试图在这里和那里抛出一些奇怪的例外 - 只是为了数据的完整性。只是为了更加安全,以便您知道我的代码是否有错误。
-
Performance: You can lookup for
Valuewith either of theKeys, which meansGetandContainsmethod require just 1 lookup (O(1)).Addrequires 2 lookups and 2 adds.Updaterequires 1 lookup and 2 adds.Removetakes 3 lookups. All similar to accepted answer.性能:您可以使用任一键查找Value,这意味着Get和Contains方法只需要1次查找(O(1))。添加需要2次查找和2次添加。更新需要1次查找和2次添加。删除需要3次查找。所有类似于接受的答案。
#5
2
I have created such a class, using C5 collection classes.
我使用C5集合类创建了这样一个类。
public class Mapper<K,T> : IEnumerable<T>{ C5.TreeDictionary<K,T> KToTMap = new TreeDictionary<K,T>(); C5.HashDictionary<T,K> TToKMap = new HashDictionary<T,K>(); /// <summary> /// Initializes a new instance of the Mapper class. /// </summary> public Mapper() { KToTMap = new TreeDictionary<K,T>(); TToKMap = new HashDictionary<T,K>(); } public void Add(K key, T value) { KToTMap.Add(key, value); TToKMap.Add(value, key); } public bool ContainsKey(K key) { return KToTMap.Contains(key); } public int Count { get { return KToTMap.Count; } } public K this[T obj] { get { return TToKMap[obj]; } } public T this[K obj] { get { return KToTMap[obj]; } } public IEnumerator<T> GetEnumerator() { return KToTMap.Values.GetEnumerator(); } System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { return KToTMap.Values.GetEnumerator(); }}#6
2
Another extension to the accepted answer. It implements IEnumerable so one can use foreach with that. I realize there are more answers with IEnumerable implementation but this one uses structs so it is garbage collector friendly.This is especially usefull in Unity engine (checked with the profiler).
接受答案的另一个扩展。它实现了IEnumerable,因此可以使用foreach。我意识到IEnumerable实现有更多的答案,但这个使用结构,因此它是垃圾收集器友好的。这在Unity引擎中特别有用(用探查器检查)。
/// <summary>/// This is a dictionary guaranteed to have only one of each value and key. /// It may be searched either by TFirst or by TSecond, giving a unique answer because it is 1 to 1./// It implements garbage-collector-friendly IEnumerable./// </summary>/// <typeparam name="TFirst">The type of the "key"</typeparam>/// <typeparam name="TSecond">The type of the "value"</typeparam>public class BiDictionary<TFirst, TSecond> : IEnumerable<BiDictionary<TFirst, TSecond>.Pair>{ public struct Pair { public TFirst First; public TSecond Second; } public struct Enumerator : IEnumerator<Pair>, IEnumerator { public Enumerator(Dictionary<TFirst, TSecond>.Enumerator dictEnumerator) { _dictEnumerator = dictEnumerator; } public Pair Current { get { Pair pair; pair.First = _dictEnumerator.Current.Key; pair.Second = _dictEnumerator.Current.Value; return pair; } } object IEnumerator.Current { get { return Current; } } public void Dispose() { _dictEnumerator.Dispose(); } public bool MoveNext() { return _dictEnumerator.MoveNext(); } public void Reset() { throw new NotSupportedException(); } private Dictionary<TFirst, TSecond>.Enumerator _dictEnumerator; } #region Exception throwing methods /// <summary> /// Tries to add the pair to the dictionary. /// Throws an exception if either element is already in the dictionary /// </summary> /// <param name="first"></param> /// <param name="second"></param> public void Add(TFirst first, TSecond second) { if (_firstToSecond.ContainsKey(first) || _secondToFirst.ContainsKey(second)) throw new ArgumentException("Duplicate first or second"); _firstToSecond.Add(first, second); _secondToFirst.Add(second, first); } /// <summary> /// Find the TSecond corresponding to the TFirst first /// Throws an exception if first is not in the dictionary. /// </summary> /// <param name="first">the key to search for</param> /// <returns>the value corresponding to first</returns> public TSecond GetByFirst(TFirst first) { TSecond second; if (!_firstToSecond.TryGetValue(first, out second)) throw new ArgumentException("first"); return second; } /// <summary> /// Find the TFirst corresponing to the Second second. /// Throws an exception if second is not in the dictionary. /// </summary> /// <param name="second">the key to search for</param> /// <returns>the value corresponding to second</returns> public TFirst GetBySecond(TSecond second) { TFirst first; if (!_secondToFirst.TryGetValue(second, out first)) throw new ArgumentException("second"); return first; } /// <summary> /// Remove the record containing first. /// If first is not in the dictionary, throws an Exception. /// </summary> /// <param name="first">the key of the record to delete</param> public void RemoveByFirst(TFirst first) { TSecond second; if (!_firstToSecond.TryGetValue(first, out second)) throw new ArgumentException("first"); _firstToSecond.Remove(first); _secondToFirst.Remove(second); } /// <summary> /// Remove the record containing second. /// If second is not in the dictionary, throws an Exception. /// </summary> /// <param name="second">the key of the record to delete</param> public void RemoveBySecond(TSecond second) { TFirst first; if (!_secondToFirst.TryGetValue(second, out first)) throw new ArgumentException("second"); _secondToFirst.Remove(second); _firstToSecond.Remove(first); } #endregion #region Try methods /// <summary> /// Tries to add the pair to the dictionary. /// Returns false if either element is already in the dictionary /// </summary> /// <param name="first"></param> /// <param name="second"></param> /// <returns>true if successfully added, false if either element are already in the dictionary</returns> public bool TryAdd(TFirst first, TSecond second) { if (_firstToSecond.ContainsKey(first) || _secondToFirst.ContainsKey(second)) return false; _firstToSecond.Add(first, second); _secondToFirst.Add(second, first); return true; } /// <summary> /// Find the TSecond corresponding to the TFirst first. /// Returns false if first is not in the dictionary. /// </summary> /// <param name="first">the key to search for</param> /// <param name="second">the corresponding value</param> /// <returns>true if first is in the dictionary, false otherwise</returns> public bool TryGetByFirst(TFirst first, out TSecond second) { return _firstToSecond.TryGetValue(first, out second); } /// <summary> /// Find the TFirst corresponding to the TSecond second. /// Returns false if second is not in the dictionary. /// </summary> /// <param name="second">the key to search for</param> /// <param name="first">the corresponding value</param> /// <returns>true if second is in the dictionary, false otherwise</returns> public bool TryGetBySecond(TSecond second, out TFirst first) { return _secondToFirst.TryGetValue(second, out first); } /// <summary> /// Remove the record containing first, if there is one. /// </summary> /// <param name="first"></param> /// <returns> If first is not in the dictionary, returns false, otherwise true</returns> public bool TryRemoveByFirst(TFirst first) { TSecond second; if (!_firstToSecond.TryGetValue(first, out second)) return false; _firstToSecond.Remove(first); _secondToFirst.Remove(second); return true; } /// <summary> /// Remove the record containing second, if there is one. /// </summary> /// <param name="second"></param> /// <returns> If second is not in the dictionary, returns false, otherwise true</returns> public bool TryRemoveBySecond(TSecond second) { TFirst first; if (!_secondToFirst.TryGetValue(second, out first)) return false; _secondToFirst.Remove(second); _firstToSecond.Remove(first); return true; } #endregion /// <summary> /// The number of pairs stored in the dictionary /// </summary> public Int32 Count { get { return _firstToSecond.Count; } } /// <summary> /// Removes all items from the dictionary. /// </summary> public void Clear() { _firstToSecond.Clear(); _secondToFirst.Clear(); } public Enumerator GetEnumerator() { //enumerator.Reset(firstToSecond.GetEnumerator()); return new Enumerator(_firstToSecond.GetEnumerator()); } IEnumerator<Pair> IEnumerable<Pair>.GetEnumerator() { return GetEnumerator(); } IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); } private Dictionary<TFirst, TSecond> _firstToSecond = new Dictionary<TFirst, TSecond>(); private Dictionary<TSecond, TFirst> _secondToFirst = new Dictionary<TSecond, TFirst>();}#7
1
A bit late, but here's an implementation I wrote a while back. It handles a few interesting edge cases, such as when the key overrides the equality check to perform partial equality. This results in the main dictionary storing A => 1 but the inverse storing 1 => A'.
有点晚了,但这是我写的一段时间的实现。它处理一些有趣的边缘情况,例如当密钥重写相等性检查以执行部分相等时。这导致主字典存储A => 1但反向存储1 => A'。
You access the inverse dictionary via the Inverse property.
您可以通过Inverse属性访问逆字典。
var map = new BidirectionalDictionary<int, int>();map.Add(1, 2);var result = map.Inverse[2]; // result is 1//// BidirectionalDictionary.cs//// Author:// Chris Chilvers <chilversc@googlemail.com>//// Copyright (c) 2009 Chris Chilvers//// Permission is hereby granted, free of charge, to any person obtaining// a copy of this software and associated documentation files (the// "Software"), to deal in the Software without restriction, including// without limitation the rights to use, copy, modify, merge, publish,// distribute, sublicense, and/or sell copies of the Software, and to// permit persons to whom the Software is furnished to do so, subject to// the following conditions://// The above copyright notice and this permission notice shall be// included in all copies or substantial portions of the Software.//// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.//using System;using System.Collections;using System.Collections.Generic;namespace Cadenza.Collections{ public class BidirectionalDictionary<TKey, TValue> : IDictionary<TKey, TValue> { private readonly IEqualityComparer<TKey> keyComparer; private readonly IEqualityComparer<TValue> valueComparer; private readonly Dictionary<TKey, TValue> keysToValues; private readonly Dictionary<TValue, TKey> valuesToKeys; private readonly BidirectionalDictionary<TValue, TKey> inverse; public BidirectionalDictionary () : this (10, null, null) {} public BidirectionalDictionary (int capacity) : this (capacity, null, null) {} public BidirectionalDictionary (IEqualityComparer<TKey> keyComparer, IEqualityComparer<TValue> valueComparer) : this (10, keyComparer, valueComparer) { } public BidirectionalDictionary (int capacity, IEqualityComparer<TKey> keyComparer, IEqualityComparer<TValue> valueComparer) { if (capacity < 0) throw new ArgumentOutOfRangeException ("capacity", capacity, "capacity cannot be less than 0"); this.keyComparer = keyComparer ?? EqualityComparer<TKey>.Default; this.valueComparer = valueComparer ?? EqualityComparer<TValue>.Default; keysToValues = new Dictionary<TKey, TValue> (capacity, this.keyComparer); valuesToKeys = new Dictionary<TValue, TKey> (capacity, this.valueComparer); inverse = new BidirectionalDictionary<TValue, TKey> (this); } private BidirectionalDictionary (BidirectionalDictionary<TValue, TKey> inverse) { this.inverse = inverse; keyComparer = inverse.valueComparer; valueComparer = inverse.keyComparer; valuesToKeys = inverse.keysToValues; keysToValues = inverse.valuesToKeys; } public BidirectionalDictionary<TValue, TKey> Inverse { get { return inverse; } } public ICollection<TKey> Keys { get { return keysToValues.Keys; } } public ICollection<TValue> Values { get { return keysToValues.Values; } } public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator () { return keysToValues.GetEnumerator (); } IEnumerator IEnumerable.GetEnumerator () { return GetEnumerator (); } void ICollection<KeyValuePair<TKey, TValue>>.CopyTo (KeyValuePair<TKey, TValue>[] array, int arrayIndex) { ((ICollection<KeyValuePair<TKey, TValue>>) keysToValues).CopyTo (array, arrayIndex); } public bool ContainsKey (TKey key) { if (key == null) throw new ArgumentNullException ("key"); return keysToValues.ContainsKey (key); } public bool ContainsValue (TValue value) { if (value == null) throw new ArgumentNullException ("value"); return valuesToKeys.ContainsKey (value); } bool ICollection<KeyValuePair<TKey, TValue>>.Contains (KeyValuePair<TKey, TValue> item) { return ((ICollection<KeyValuePair<TKey, TValue>>) keysToValues).Contains (item); } public bool TryGetKey (TValue value, out TKey key) { if (value == null) throw new ArgumentNullException ("value"); return valuesToKeys.TryGetValue (value, out key); } public bool TryGetValue (TKey key, out TValue value) { if (key == null) throw new ArgumentNullException ("key"); return keysToValues.TryGetValue (key, out value); } public TValue this[TKey key] { get { return keysToValues [key]; } set { if (key == null) throw new ArgumentNullException ("key"); if (value == null) throw new ArgumentNullException ("value"); //foo[5] = "bar"; foo[6] = "bar"; should not be valid //as it would have to remove foo[5], which is unexpected. if (ValueBelongsToOtherKey (key, value)) throw new ArgumentException ("Value already exists", "value"); TValue oldValue; if (keysToValues.TryGetValue (key, out oldValue)) { // Use the current key for this value to stay consistent // with Dictionary<TKey, TValue> which does not alter // the key if it exists. TKey oldKey = valuesToKeys [oldValue]; keysToValues [oldKey] = value; valuesToKeys.Remove (oldValue); valuesToKeys [value] = oldKey; } else { keysToValues [key] = value; valuesToKeys [value] = key; } } } public int Count { get { return keysToValues.Count; } } bool ICollection<KeyValuePair<TKey, TValue>>.IsReadOnly { get { return false; } } public void Add (TKey key, TValue value) { if (key == null) throw new ArgumentNullException ("key"); if (value == null) throw new ArgumentNullException ("value"); if (keysToValues.ContainsKey (key)) throw new ArgumentException ("Key already exists", "key"); if (valuesToKeys.ContainsKey (value)) throw new ArgumentException ("Value already exists", "value"); keysToValues.Add (key, value); valuesToKeys.Add (value, key); } public void Replace (TKey key, TValue value) { if (key == null) throw new ArgumentNullException ("key"); if (value == null) throw new ArgumentNullException ("value"); // replaces a key value pair, if the key or value already exists those mappings will be replaced. // e.g. you have; a -> b, b -> a; c -> d, d -> c // you add the mapping; a -> d, d -> a // this will remove both of the original mappings Remove (key); inverse.Remove (value); Add (key, value); } void ICollection<KeyValuePair<TKey, TValue>>.Add (KeyValuePair<TKey, TValue> item) { Add (item.Key, item.Value); } public bool Remove (TKey key) { if (key == null) throw new ArgumentNullException ("key"); TValue value; if (keysToValues.TryGetValue (key, out value)) { keysToValues.Remove (key); valuesToKeys.Remove (value); return true; } else { return false; } } bool ICollection<KeyValuePair<TKey, TValue>>.Remove (KeyValuePair<TKey, TValue> item) { bool removed = ((ICollection<KeyValuePair<TKey, TValue>>) keysToValues).Remove (item); if (removed) valuesToKeys.Remove (item.Value); return removed; } public void Clear () { keysToValues.Clear (); valuesToKeys.Clear (); } private bool ValueBelongsToOtherKey (TKey key, TValue value) { TKey otherKey; if (valuesToKeys.TryGetValue (value, out otherKey)) // if the keys are not equal the value belongs to another key return !keyComparer.Equals (key, otherKey); else // value doesn't exist in map, thus it cannot belong to another key return false; } }}Original source and tests on github.
原始资源和github上的测试。
#1
67
OK, here is my attempt (building on Jon's - thanks), archived here and open for improvement :
好的,这是我的尝试(建立在Jon的 - 感谢),存档在这里并开放改进:
/// <summary>/// This is a dictionary guaranteed to have only one of each value and key. /// It may be searched either by TFirst or by TSecond, giving a unique answer because it is 1 to 1./// </summary>/// <typeparam name="TFirst">The type of the "key"</typeparam>/// <typeparam name="TSecond">The type of the "value"</typeparam>public class BiDictionaryOneToOne<TFirst, TSecond>{ IDictionary<TFirst, TSecond> firstToSecond = new Dictionary<TFirst, TSecond>(); IDictionary<TSecond, TFirst> secondToFirst = new Dictionary<TSecond, TFirst>(); #region Exception throwing methods /// <summary> /// Tries to add the pair to the dictionary. /// Throws an exception if either element is already in the dictionary /// </summary> /// <param name="first"></param> /// <param name="second"></param> public void Add(TFirst first, TSecond second) { if (firstToSecond.ContainsKey(first) || secondToFirst.ContainsKey(second)) throw new ArgumentException("Duplicate first or second"); firstToSecond.Add(first, second); secondToFirst.Add(second, first); } /// <summary> /// Find the TSecond corresponding to the TFirst first /// Throws an exception if first is not in the dictionary. /// </summary> /// <param name="first">the key to search for</param> /// <returns>the value corresponding to first</returns> public TSecond GetByFirst(TFirst first) { TSecond second; if (!firstToSecond.TryGetValue(first, out second)) throw new ArgumentException("first"); return second; } /// <summary> /// Find the TFirst corresponing to the Second second. /// Throws an exception if second is not in the dictionary. /// </summary> /// <param name="second">the key to search for</param> /// <returns>the value corresponding to second</returns> public TFirst GetBySecond(TSecond second) { TFirst first; if (!secondToFirst.TryGetValue(second, out first)) throw new ArgumentException("second"); return first; } /// <summary> /// Remove the record containing first. /// If first is not in the dictionary, throws an Exception. /// </summary> /// <param name="first">the key of the record to delete</param> public void RemoveByFirst(TFirst first) { TSecond second; if (!firstToSecond.TryGetValue(first, out second)) throw new ArgumentException("first"); firstToSecond.Remove(first); secondToFirst.Remove(second); } /// <summary> /// Remove the record containing second. /// If second is not in the dictionary, throws an Exception. /// </summary> /// <param name="second">the key of the record to delete</param> public void RemoveBySecond(TSecond second) { TFirst first; if (!secondToFirst.TryGetValue(second, out first)) throw new ArgumentException("second"); secondToFirst.Remove(second); firstToSecond.Remove(first); } #endregion #region Try methods /// <summary> /// Tries to add the pair to the dictionary. /// Returns false if either element is already in the dictionary /// </summary> /// <param name="first"></param> /// <param name="second"></param> /// <returns>true if successfully added, false if either element are already in the dictionary</returns> public Boolean TryAdd(TFirst first, TSecond second) { if (firstToSecond.ContainsKey(first) || secondToFirst.ContainsKey(second)) return false; firstToSecond.Add(first, second); secondToFirst.Add(second, first); return true; } /// <summary> /// Find the TSecond corresponding to the TFirst first. /// Returns false if first is not in the dictionary. /// </summary> /// <param name="first">the key to search for</param> /// <param name="second">the corresponding value</param> /// <returns>true if first is in the dictionary, false otherwise</returns> public Boolean TryGetByFirst(TFirst first, out TSecond second) { return firstToSecond.TryGetValue(first, out second); } /// <summary> /// Find the TFirst corresponding to the TSecond second. /// Returns false if second is not in the dictionary. /// </summary> /// <param name="second">the key to search for</param> /// <param name="first">the corresponding value</param> /// <returns>true if second is in the dictionary, false otherwise</returns> public Boolean TryGetBySecond(TSecond second, out TFirst first) { return secondToFirst.TryGetValue(second, out first); } /// <summary> /// Remove the record containing first, if there is one. /// </summary> /// <param name="first"></param> /// <returns> If first is not in the dictionary, returns false, otherwise true</returns> public Boolean TryRemoveByFirst(TFirst first) { TSecond second; if (!firstToSecond.TryGetValue(first, out second)) return false; firstToSecond.Remove(first); secondToFirst.Remove(second); return true; } /// <summary> /// Remove the record containing second, if there is one. /// </summary> /// <param name="second"></param> /// <returns> If second is not in the dictionary, returns false, otherwise true</returns> public Boolean TryRemoveBySecond(TSecond second) { TFirst first; if (!secondToFirst.TryGetValue(second, out first)) return false; secondToFirst.Remove(second); firstToSecond.Remove(first); return true; } #endregion /// <summary> /// The number of pairs stored in the dictionary /// </summary> public Int32 Count { get { return firstToSecond.Count; } } /// <summary> /// Removes all items from the dictionary. /// </summary> public void Clear() { firstToSecond.Clear(); secondToFirst.Clear(); }}#2
16
A more complete implementation of bidirectional dictionary:
双向字典的更完整实现:
-
Supports almost all interfaces of original
Dictionary<TKey,TValue>(except infrastructure interfaces):IDictionary<TKey, TValue>IReadOnlyDictionary<TKey, TValue>IDictionary-
ICollection<KeyValuePair<TKey, TValue>>(this one and below are the base interfaces of the ones above) ICollectionIReadOnlyCollection<KeyValuePair<TKey, TValue>>IEnumerable<KeyValuePair<TKey, TValue>>IEnumerable
ICollection
>(这一个及以下是以上的基本接口) -
Serialization using
SerializableAttribute. -
Debug view using
DebuggerDisplayAttribute(with Count info) andDebuggerTypeProxyAttribute(for displaying key-value pairs in watches). - Reverse dictionary is available as
IDictionary<TValue, TKey> Reverseproperty and also implements all interfaces mentioned above. All operations on either dictionaries modify both.
支持原始Dictionary
使用SerializableAttribute进行序列化。
使用DebuggerDisplayAttribute(带有Count信息)和DebuggerTypeProxyAttribute(用于在watch中显示键值对)的Debug视图。
反向字典可用作IDictionary
Usage:
var dic = new BiDictionary<int, string>();dic.Add(1, "1");dic[2] = "2";dic.Reverse.Add("3", 3);dic.Reverse["4"] = 4;dic.Clear();Code is available in my private framework on GitHub: BiDictionary(TFirst,TSecond).cs (permalink, search).
代码可以在GitHub的私有框架中找到:BiDictionary(TFirst,TSecond).cs(永久链接,搜索)。
Copy:
[Serializable][DebuggerDisplay ("Count = {Count}"), DebuggerTypeProxy (typeof(DictionaryDebugView<,>))]public class BiDictionary<TFirst, TSecond> : IDictionary<TFirst, TSecond>, IReadOnlyDictionary<TFirst, TSecond>, IDictionary{ private readonly IDictionary<TFirst, TSecond> _firstToSecond = new Dictionary<TFirst, TSecond>(); [NonSerialized] private readonly IDictionary<TSecond, TFirst> _secondToFirst = new Dictionary<TSecond, TFirst>(); [NonSerialized] private readonly ReverseDictionary _reverseDictionary; public BiDictionary () { _reverseDictionary = new ReverseDictionary(this); } public IDictionary<TSecond, TFirst> Reverse { get { return _reverseDictionary; } } public int Count { get { return _firstToSecond.Count; } } object ICollection.SyncRoot { get { return ((ICollection)_firstToSecond).SyncRoot; } } bool ICollection.IsSynchronized { get { return ((ICollection)_firstToSecond).IsSynchronized; } } bool IDictionary.IsFixedSize { get { return ((IDictionary)_firstToSecond).IsFixedSize; } } public bool IsReadOnly { get { return _firstToSecond.IsReadOnly || _secondToFirst.IsReadOnly; } } public TSecond this [TFirst key] { get { return _firstToSecond[key]; } set { _firstToSecond[key] = value; _secondToFirst[value] = key; } } object IDictionary.this [object key] { get { return ((IDictionary)_firstToSecond)[key]; } set { ((IDictionary)_firstToSecond)[key] = value; ((IDictionary)_secondToFirst)[value] = key; } } public ICollection<TFirst> Keys { get { return _firstToSecond.Keys; } } ICollection IDictionary.Keys { get { return ((IDictionary)_firstToSecond).Keys; } } IEnumerable<TFirst> IReadOnlyDictionary<TFirst, TSecond>.Keys { get { return ((IReadOnlyDictionary<TFirst, TSecond>)_firstToSecond).Keys; } } public ICollection<TSecond> Values { get { return _firstToSecond.Values; } } ICollection IDictionary.Values { get { return ((IDictionary)_firstToSecond).Values; } } IEnumerable<TSecond> IReadOnlyDictionary<TFirst, TSecond>.Values { get { return ((IReadOnlyDictionary<TFirst, TSecond>)_firstToSecond).Values; } } public IEnumerator<KeyValuePair<TFirst, TSecond>> GetEnumerator () { return _firstToSecond.GetEnumerator(); } IEnumerator IEnumerable.GetEnumerator () { return GetEnumerator(); } IDictionaryEnumerator IDictionary.GetEnumerator () { return ((IDictionary)_firstToSecond).GetEnumerator(); } public void Add (TFirst key, TSecond value) { _firstToSecond.Add(key, value); _secondToFirst.Add(value, key); } void IDictionary.Add (object key, object value) { ((IDictionary)_firstToSecond).Add(key, value); ((IDictionary)_secondToFirst).Add(value, key); } public void Add (KeyValuePair<TFirst, TSecond> item) { _firstToSecond.Add(item); _secondToFirst.Add(item.Reverse()); } public bool ContainsKey (TFirst key) { return _firstToSecond.ContainsKey(key); } public bool Contains (KeyValuePair<TFirst, TSecond> item) { return _firstToSecond.Contains(item); } public bool TryGetValue (TFirst key, out TSecond value) { return _firstToSecond.TryGetValue(key, out value); } public bool Remove (TFirst key) { TSecond value; if (_firstToSecond.TryGetValue(key, out value)) { _firstToSecond.Remove(key); _secondToFirst.Remove(value); return true; } else return false; } void IDictionary.Remove (object key) { var firstToSecond = (IDictionary)_firstToSecond; if (!firstToSecond.Contains(key)) return; var value = firstToSecond[key]; firstToSecond.Remove(key); ((IDictionary)_secondToFirst).Remove(value); } public bool Remove (KeyValuePair<TFirst, TSecond> item) { return _firstToSecond.Remove(item); } public bool Contains (object key) { return ((IDictionary)_firstToSecond).Contains(key); } public void Clear () { _firstToSecond.Clear(); _secondToFirst.Clear(); } public void CopyTo (KeyValuePair<TFirst, TSecond>[] array, int arrayIndex) { _firstToSecond.CopyTo(array, arrayIndex); } void ICollection.CopyTo (Array array, int index) { ((IDictionary)_firstToSecond).CopyTo(array, index); } [OnDeserialized] internal void OnDeserialized (StreamingContext context) { _secondToFirst.Clear(); foreach (var item in _firstToSecond) _secondToFirst.Add(item.Value, item.Key); } private class ReverseDictionary : IDictionary<TSecond, TFirst>, IReadOnlyDictionary<TSecond, TFirst>, IDictionary { private readonly BiDictionary<TFirst, TSecond> _owner; public ReverseDictionary (BiDictionary<TFirst, TSecond> owner) { _owner = owner; } public int Count { get { return _owner._secondToFirst.Count; } } object ICollection.SyncRoot { get { return ((ICollection)_owner._secondToFirst).SyncRoot; } } bool ICollection.IsSynchronized { get { return ((ICollection)_owner._secondToFirst).IsSynchronized; } } bool IDictionary.IsFixedSize { get { return ((IDictionary)_owner._secondToFirst).IsFixedSize; } } public bool IsReadOnly { get { return _owner._secondToFirst.IsReadOnly || _owner._firstToSecond.IsReadOnly; } } public TFirst this [TSecond key] { get { return _owner._secondToFirst[key]; } set { _owner._secondToFirst[key] = value; _owner._firstToSecond[value] = key; } } object IDictionary.this [object key] { get { return ((IDictionary)_owner._secondToFirst)[key]; } set { ((IDictionary)_owner._secondToFirst)[key] = value; ((IDictionary)_owner._firstToSecond)[value] = key; } } public ICollection<TSecond> Keys { get { return _owner._secondToFirst.Keys; } } ICollection IDictionary.Keys { get { return ((IDictionary)_owner._secondToFirst).Keys; } } IEnumerable<TSecond> IReadOnlyDictionary<TSecond, TFirst>.Keys { get { return ((IReadOnlyDictionary<TSecond, TFirst>)_owner._secondToFirst).Keys; } } public ICollection<TFirst> Values { get { return _owner._secondToFirst.Values; } } ICollection IDictionary.Values { get { return ((IDictionary)_owner._secondToFirst).Values; } } IEnumerable<TFirst> IReadOnlyDictionary<TSecond, TFirst>.Values { get { return ((IReadOnlyDictionary<TSecond, TFirst>)_owner._secondToFirst).Values; } } public IEnumerator<KeyValuePair<TSecond, TFirst>> GetEnumerator () { return _owner._secondToFirst.GetEnumerator(); } IEnumerator IEnumerable.GetEnumerator () { return GetEnumerator(); } IDictionaryEnumerator IDictionary.GetEnumerator () { return ((IDictionary)_owner._secondToFirst).GetEnumerator(); } public void Add (TSecond key, TFirst value) { _owner._secondToFirst.Add(key, value); _owner._firstToSecond.Add(value, key); } void IDictionary.Add (object key, object value) { ((IDictionary)_owner._secondToFirst).Add(key, value); ((IDictionary)_owner._firstToSecond).Add(value, key); } public void Add (KeyValuePair<TSecond, TFirst> item) { _owner._secondToFirst.Add(item); _owner._firstToSecond.Add(item.Reverse()); } public bool ContainsKey (TSecond key) { return _owner._secondToFirst.ContainsKey(key); } public bool Contains (KeyValuePair<TSecond, TFirst> item) { return _owner._secondToFirst.Contains(item); } public bool TryGetValue (TSecond key, out TFirst value) { return _owner._secondToFirst.TryGetValue(key, out value); } public bool Remove (TSecond key) { TFirst value; if (_owner._secondToFirst.TryGetValue(key, out value)) { _owner._secondToFirst.Remove(key); _owner._firstToSecond.Remove(value); return true; } else return false; } void IDictionary.Remove (object key) { var firstToSecond = (IDictionary)_owner._secondToFirst; if (!firstToSecond.Contains(key)) return; var value = firstToSecond[key]; firstToSecond.Remove(key); ((IDictionary)_owner._firstToSecond).Remove(value); } public bool Remove (KeyValuePair<TSecond, TFirst> item) { return _owner._secondToFirst.Remove(item); } public bool Contains (object key) { return ((IDictionary)_owner._secondToFirst).Contains(key); } public void Clear () { _owner._secondToFirst.Clear(); _owner._firstToSecond.Clear(); } public void CopyTo (KeyValuePair<TSecond, TFirst>[] array, int arrayIndex) { _owner._secondToFirst.CopyTo(array, arrayIndex); } void ICollection.CopyTo (Array array, int index) { ((IDictionary)_owner._secondToFirst).CopyTo(array, index); } }}internal class DictionaryDebugView<TKey, TValue>{ private readonly IDictionary<TKey, TValue> _dictionary; [DebuggerBrowsable (DebuggerBrowsableState.RootHidden)] public KeyValuePair<TKey, TValue>[] Items { get { var array = new KeyValuePair<TKey, TValue>[_dictionary.Count]; _dictionary.CopyTo(array, 0); return array; } } public DictionaryDebugView (IDictionary<TKey, TValue> dictionary) { if (dictionary == null) throw new ArgumentNullException("dictionary"); _dictionary = dictionary; }}public static class KeyValuePairExts{ public static KeyValuePair<TValue, TKey> Reverse<TKey, TValue> (this KeyValuePair<TKey, TValue> @this) { return new KeyValuePair<TValue, TKey>(@this.Value, @this.Key); }}#3
11
The question you refer to also shows a one-to-one implementation in this answer. Adding RemoveByFirst and RemoveBySecond would be trivial - as would implementing extra interfaces etc.
您提到的问题还显示了此答案中的一对一实现。添加RemoveByFirst和RemoveBySecond将是微不足道的 - 正如实现额外的接口等。
#4
3
This is same as accepted answer, but I provided Update methods as well, and over all little more fleshed out:
这与已接受的答案相同,但我也提供了更新方法,并且更加充实了:
public class BiDictionary<TKey1, TKey2> : IEnumerable<Tuple<TKey1, TKey2>>{ Dictionary<TKey1, TKey2> _forwards; Dictionary<TKey2, TKey1> _reverses; public int Count { get { if (_forwards.Count != _reverses.Count) throw new Exception("somewhere logic went wrong and your data got corrupt"); return _forwards.Count; } } public ICollection<TKey1> Key1s { get { return _forwards.Keys; } } public ICollection<TKey2> Key2s { get { return _reverses.Keys; } } public BiDictionary(IEqualityComparer<TKey1> comparer1 = null, IEqualityComparer<TKey2> comparer2 = null) { _forwards = new Dictionary<TKey1, TKey2>(comparer1); _reverses = new Dictionary<TKey2, TKey1>(comparer2); } public bool ContainsKey1(TKey1 key) { return ContainsKey(key, _forwards); } private static bool ContainsKey<S, T>(S key, Dictionary<S, T> dict) { return dict.ContainsKey(key); } public bool ContainsKey2(TKey2 key) { return ContainsKey(key, _reverses); } public TKey2 GetValueByKey1(TKey1 key) { return GetValueByKey(key, _forwards); } private static T GetValueByKey<S, T>(S key, Dictionary<S, T> dict) { return dict[key]; } public TKey1 GetValueByKey2(TKey2 key) { return GetValueByKey(key, _reverses); } public bool TryGetValueByKey1(TKey1 key, out TKey2 value) { return TryGetValue(key, _forwards, out value); } private static bool TryGetValue<S, T>(S key, Dictionary<S, T> dict, out T value) { return dict.TryGetValue(key, out value); } public bool TryGetValueByKey2(TKey2 key, out TKey1 value) { return TryGetValue(key, _reverses, out value); } public bool Add(TKey1 key1, TKey2 key2) { if (ContainsKey1(key1) || ContainsKey2(key2)) // very important return false; AddOrUpdate(key1, key2); return true; } public void AddOrUpdateByKey1(TKey1 key1, TKey2 key2) { if (!UpdateByKey1(key1, key2)) AddOrUpdate(key1, key2); } // dont make this public; a dangerous method used cautiously in this class private void AddOrUpdate(TKey1 key1, TKey2 key2) { _forwards[key1] = key2; _reverses[key2] = key1; } public void AddOrUpdateKeyByKey2(TKey2 key2, TKey1 key1) { if (!UpdateByKey2(key2, key1)) AddOrUpdate(key1, key2); } public bool UpdateKey1(TKey1 oldKey, TKey1 newKey) { return UpdateKey(oldKey, _forwards, newKey, (key1, key2) => AddOrUpdate(key1, key2)); } private static bool UpdateKey<S, T>(S oldKey, Dictionary<S, T> dict, S newKey, Action<S, T> updater) { T otherKey; if (!TryGetValue(oldKey, dict, out otherKey) || ContainsKey(newKey, dict)) return false; Remove(oldKey, dict); updater(newKey, otherKey); return true; } public bool UpdateKey2(TKey2 oldKey, TKey2 newKey) { return UpdateKey(oldKey, _reverses, newKey, (key1, key2) => AddOrUpdate(key2, key1)); } public bool UpdateByKey1(TKey1 key1, TKey2 key2) { return UpdateByKey(key1, _forwards, _reverses, key2, (k1, k2) => AddOrUpdate(k1, k2)); } private static bool UpdateByKey<S, T>(S key1, Dictionary<S, T> forwards, Dictionary<T, S> reverses, T key2, Action<S, T> updater) { T otherKey; if (!TryGetValue(key1, forwards, out otherKey) || ContainsKey(key2, reverses)) return false; if (!Remove(otherKey, reverses)) throw new Exception("somewhere logic went wrong and your data got corrupt"); updater(key1, key2); return true; } public bool UpdateByKey2(TKey2 key2, TKey1 key1) { return UpdateByKey(key2, _reverses, _forwards, key1, (k1, k2) => AddOrUpdate(k2, k1)); } public bool RemoveByKey1(TKey1 key) { return RemoveByKey(key, _forwards, _reverses); } private static bool RemoveByKey<S, T>(S key, Dictionary<S, T> keyDict, Dictionary<T, S> valueDict) { T otherKey; if (!TryGetValue(key, keyDict, out otherKey)) return false; if (!Remove(key, keyDict) || !Remove(otherKey, valueDict)) throw new Exception("somewhere logic went wrong and your data got corrupt"); return true; } private static bool Remove<S, T>(S key, Dictionary<S, T> dict) { return dict.Remove(key); } public bool RemoveByKey2(TKey2 key) { return RemoveByKey(key, _reverses, _forwards); } public void Clear() { _forwards.Clear(); _reverses.Clear(); } public IEnumerator<Tuple<TKey1, TKey2>> GetEnumerator() { if (_forwards.Count != _reverses.Count) throw new Exception("somewhere logic went wrong and your data got corrupt"); foreach (var item in _forwards) yield return Tuple.Create(item.Key, item.Value); } IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); }}Similar to my answer here
与我的答案类似
Few things to note:
几点注意事项:
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I have implemented only
IEnumerable<>. I don't thinkICollection<>makes sense here since the method names all could be way different for this special collection structure. Up to you to decide what should go insideIEnumerable<>. So now you have collection initializer syntax too, like我只实现了IEnumerable <>。我不认为ICollection <>在这里有意义,因为这个特殊的集合结构的方法名称都可能有所不同。由您决定IEnumerable <>内应该包含哪些内容。所以现在你也有了集合初始化器语法,比如
var p = new BiDictionary<int, string> { 1, "a" }, { 2, "b" } }; -
I have attempted for some weird exceptions to be thrown here and there - just for data integrity. Just to be on the safer side so that you know if ever my code has bugs.
我试图在这里和那里抛出一些奇怪的例外 - 只是为了数据的完整性。只是为了更加安全,以便您知道我的代码是否有错误。
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Performance: You can lookup for
Valuewith either of theKeys, which meansGetandContainsmethod require just 1 lookup (O(1)).Addrequires 2 lookups and 2 adds.Updaterequires 1 lookup and 2 adds.Removetakes 3 lookups. All similar to accepted answer.性能:您可以使用任一键查找Value,这意味着Get和Contains方法只需要1次查找(O(1))。添加需要2次查找和2次添加。更新需要1次查找和2次添加。删除需要3次查找。所有类似于接受的答案。
#5
2
I have created such a class, using C5 collection classes.
我使用C5集合类创建了这样一个类。
public class Mapper<K,T> : IEnumerable<T>{ C5.TreeDictionary<K,T> KToTMap = new TreeDictionary<K,T>(); C5.HashDictionary<T,K> TToKMap = new HashDictionary<T,K>(); /// <summary> /// Initializes a new instance of the Mapper class. /// </summary> public Mapper() { KToTMap = new TreeDictionary<K,T>(); TToKMap = new HashDictionary<T,K>(); } public void Add(K key, T value) { KToTMap.Add(key, value); TToKMap.Add(value, key); } public bool ContainsKey(K key) { return KToTMap.Contains(key); } public int Count { get { return KToTMap.Count; } } public K this[T obj] { get { return TToKMap[obj]; } } public T this[K obj] { get { return KToTMap[obj]; } } public IEnumerator<T> GetEnumerator() { return KToTMap.Values.GetEnumerator(); } System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { return KToTMap.Values.GetEnumerator(); }}#6
2
Another extension to the accepted answer. It implements IEnumerable so one can use foreach with that. I realize there are more answers with IEnumerable implementation but this one uses structs so it is garbage collector friendly.This is especially usefull in Unity engine (checked with the profiler).
接受答案的另一个扩展。它实现了IEnumerable,因此可以使用foreach。我意识到IEnumerable实现有更多的答案,但这个使用结构,因此它是垃圾收集器友好的。这在Unity引擎中特别有用(用探查器检查)。
/// <summary>/// This is a dictionary guaranteed to have only one of each value and key. /// It may be searched either by TFirst or by TSecond, giving a unique answer because it is 1 to 1./// It implements garbage-collector-friendly IEnumerable./// </summary>/// <typeparam name="TFirst">The type of the "key"</typeparam>/// <typeparam name="TSecond">The type of the "value"</typeparam>public class BiDictionary<TFirst, TSecond> : IEnumerable<BiDictionary<TFirst, TSecond>.Pair>{ public struct Pair { public TFirst First; public TSecond Second; } public struct Enumerator : IEnumerator<Pair>, IEnumerator { public Enumerator(Dictionary<TFirst, TSecond>.Enumerator dictEnumerator) { _dictEnumerator = dictEnumerator; } public Pair Current { get { Pair pair; pair.First = _dictEnumerator.Current.Key; pair.Second = _dictEnumerator.Current.Value; return pair; } } object IEnumerator.Current { get { return Current; } } public void Dispose() { _dictEnumerator.Dispose(); } public bool MoveNext() { return _dictEnumerator.MoveNext(); } public void Reset() { throw new NotSupportedException(); } private Dictionary<TFirst, TSecond>.Enumerator _dictEnumerator; } #region Exception throwing methods /// <summary> /// Tries to add the pair to the dictionary. /// Throws an exception if either element is already in the dictionary /// </summary> /// <param name="first"></param> /// <param name="second"></param> public void Add(TFirst first, TSecond second) { if (_firstToSecond.ContainsKey(first) || _secondToFirst.ContainsKey(second)) throw new ArgumentException("Duplicate first or second"); _firstToSecond.Add(first, second); _secondToFirst.Add(second, first); } /// <summary> /// Find the TSecond corresponding to the TFirst first /// Throws an exception if first is not in the dictionary. /// </summary> /// <param name="first">the key to search for</param> /// <returns>the value corresponding to first</returns> public TSecond GetByFirst(TFirst first) { TSecond second; if (!_firstToSecond.TryGetValue(first, out second)) throw new ArgumentException("first"); return second; } /// <summary> /// Find the TFirst corresponing to the Second second. /// Throws an exception if second is not in the dictionary. /// </summary> /// <param name="second">the key to search for</param> /// <returns>the value corresponding to second</returns> public TFirst GetBySecond(TSecond second) { TFirst first; if (!_secondToFirst.TryGetValue(second, out first)) throw new ArgumentException("second"); return first; } /// <summary> /// Remove the record containing first. /// If first is not in the dictionary, throws an Exception. /// </summary> /// <param name="first">the key of the record to delete</param> public void RemoveByFirst(TFirst first) { TSecond second; if (!_firstToSecond.TryGetValue(first, out second)) throw new ArgumentException("first"); _firstToSecond.Remove(first); _secondToFirst.Remove(second); } /// <summary> /// Remove the record containing second. /// If second is not in the dictionary, throws an Exception. /// </summary> /// <param name="second">the key of the record to delete</param> public void RemoveBySecond(TSecond second) { TFirst first; if (!_secondToFirst.TryGetValue(second, out first)) throw new ArgumentException("second"); _secondToFirst.Remove(second); _firstToSecond.Remove(first); } #endregion #region Try methods /// <summary> /// Tries to add the pair to the dictionary. /// Returns false if either element is already in the dictionary /// </summary> /// <param name="first"></param> /// <param name="second"></param> /// <returns>true if successfully added, false if either element are already in the dictionary</returns> public bool TryAdd(TFirst first, TSecond second) { if (_firstToSecond.ContainsKey(first) || _secondToFirst.ContainsKey(second)) return false; _firstToSecond.Add(first, second); _secondToFirst.Add(second, first); return true; } /// <summary> /// Find the TSecond corresponding to the TFirst first. /// Returns false if first is not in the dictionary. /// </summary> /// <param name="first">the key to search for</param> /// <param name="second">the corresponding value</param> /// <returns>true if first is in the dictionary, false otherwise</returns> public bool TryGetByFirst(TFirst first, out TSecond second) { return _firstToSecond.TryGetValue(first, out second); } /// <summary> /// Find the TFirst corresponding to the TSecond second. /// Returns false if second is not in the dictionary. /// </summary> /// <param name="second">the key to search for</param> /// <param name="first">the corresponding value</param> /// <returns>true if second is in the dictionary, false otherwise</returns> public bool TryGetBySecond(TSecond second, out TFirst first) { return _secondToFirst.TryGetValue(second, out first); } /// <summary> /// Remove the record containing first, if there is one. /// </summary> /// <param name="first"></param> /// <returns> If first is not in the dictionary, returns false, otherwise true</returns> public bool TryRemoveByFirst(TFirst first) { TSecond second; if (!_firstToSecond.TryGetValue(first, out second)) return false; _firstToSecond.Remove(first); _secondToFirst.Remove(second); return true; } /// <summary> /// Remove the record containing second, if there is one. /// </summary> /// <param name="second"></param> /// <returns> If second is not in the dictionary, returns false, otherwise true</returns> public bool TryRemoveBySecond(TSecond second) { TFirst first; if (!_secondToFirst.TryGetValue(second, out first)) return false; _secondToFirst.Remove(second); _firstToSecond.Remove(first); return true; } #endregion /// <summary> /// The number of pairs stored in the dictionary /// </summary> public Int32 Count { get { return _firstToSecond.Count; } } /// <summary> /// Removes all items from the dictionary. /// </summary> public void Clear() { _firstToSecond.Clear(); _secondToFirst.Clear(); } public Enumerator GetEnumerator() { //enumerator.Reset(firstToSecond.GetEnumerator()); return new Enumerator(_firstToSecond.GetEnumerator()); } IEnumerator<Pair> IEnumerable<Pair>.GetEnumerator() { return GetEnumerator(); } IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); } private Dictionary<TFirst, TSecond> _firstToSecond = new Dictionary<TFirst, TSecond>(); private Dictionary<TSecond, TFirst> _secondToFirst = new Dictionary<TSecond, TFirst>();}#7
1
A bit late, but here's an implementation I wrote a while back. It handles a few interesting edge cases, such as when the key overrides the equality check to perform partial equality. This results in the main dictionary storing A => 1 but the inverse storing 1 => A'.
有点晚了,但这是我写的一段时间的实现。它处理一些有趣的边缘情况,例如当密钥重写相等性检查以执行部分相等时。这导致主字典存储A => 1但反向存储1 => A'。
You access the inverse dictionary via the Inverse property.
您可以通过Inverse属性访问逆字典。
var map = new BidirectionalDictionary<int, int>();map.Add(1, 2);var result = map.Inverse[2]; // result is 1//// BidirectionalDictionary.cs//// Author:// Chris Chilvers <chilversc@googlemail.com>//// Copyright (c) 2009 Chris Chilvers//// Permission is hereby granted, free of charge, to any person obtaining// a copy of this software and associated documentation files (the// "Software"), to deal in the Software without restriction, including// without limitation the rights to use, copy, modify, merge, publish,// distribute, sublicense, and/or sell copies of the Software, and to// permit persons to whom the Software is furnished to do so, subject to// the following conditions://// The above copyright notice and this permission notice shall be// included in all copies or substantial portions of the Software.//// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.//using System;using System.Collections;using System.Collections.Generic;namespace Cadenza.Collections{ public class BidirectionalDictionary<TKey, TValue> : IDictionary<TKey, TValue> { private readonly IEqualityComparer<TKey> keyComparer; private readonly IEqualityComparer<TValue> valueComparer; private readonly Dictionary<TKey, TValue> keysToValues; private readonly Dictionary<TValue, TKey> valuesToKeys; private readonly BidirectionalDictionary<TValue, TKey> inverse; public BidirectionalDictionary () : this (10, null, null) {} public BidirectionalDictionary (int capacity) : this (capacity, null, null) {} public BidirectionalDictionary (IEqualityComparer<TKey> keyComparer, IEqualityComparer<TValue> valueComparer) : this (10, keyComparer, valueComparer) { } public BidirectionalDictionary (int capacity, IEqualityComparer<TKey> keyComparer, IEqualityComparer<TValue> valueComparer) { if (capacity < 0) throw new ArgumentOutOfRangeException ("capacity", capacity, "capacity cannot be less than 0"); this.keyComparer = keyComparer ?? EqualityComparer<TKey>.Default; this.valueComparer = valueComparer ?? EqualityComparer<TValue>.Default; keysToValues = new Dictionary<TKey, TValue> (capacity, this.keyComparer); valuesToKeys = new Dictionary<TValue, TKey> (capacity, this.valueComparer); inverse = new BidirectionalDictionary<TValue, TKey> (this); } private BidirectionalDictionary (BidirectionalDictionary<TValue, TKey> inverse) { this.inverse = inverse; keyComparer = inverse.valueComparer; valueComparer = inverse.keyComparer; valuesToKeys = inverse.keysToValues; keysToValues = inverse.valuesToKeys; } public BidirectionalDictionary<TValue, TKey> Inverse { get { return inverse; } } public ICollection<TKey> Keys { get { return keysToValues.Keys; } } public ICollection<TValue> Values { get { return keysToValues.Values; } } public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator () { return keysToValues.GetEnumerator (); } IEnumerator IEnumerable.GetEnumerator () { return GetEnumerator (); } void ICollection<KeyValuePair<TKey, TValue>>.CopyTo (KeyValuePair<TKey, TValue>[] array, int arrayIndex) { ((ICollection<KeyValuePair<TKey, TValue>>) keysToValues).CopyTo (array, arrayIndex); } public bool ContainsKey (TKey key) { if (key == null) throw new ArgumentNullException ("key"); return keysToValues.ContainsKey (key); } public bool ContainsValue (TValue value) { if (value == null) throw new ArgumentNullException ("value"); return valuesToKeys.ContainsKey (value); } bool ICollection<KeyValuePair<TKey, TValue>>.Contains (KeyValuePair<TKey, TValue> item) { return ((ICollection<KeyValuePair<TKey, TValue>>) keysToValues).Contains (item); } public bool TryGetKey (TValue value, out TKey key) { if (value == null) throw new ArgumentNullException ("value"); return valuesToKeys.TryGetValue (value, out key); } public bool TryGetValue (TKey key, out TValue value) { if (key == null) throw new ArgumentNullException ("key"); return keysToValues.TryGetValue (key, out value); } public TValue this[TKey key] { get { return keysToValues [key]; } set { if (key == null) throw new ArgumentNullException ("key"); if (value == null) throw new ArgumentNullException ("value"); //foo[5] = "bar"; foo[6] = "bar"; should not be valid //as it would have to remove foo[5], which is unexpected. if (ValueBelongsToOtherKey (key, value)) throw new ArgumentException ("Value already exists", "value"); TValue oldValue; if (keysToValues.TryGetValue (key, out oldValue)) { // Use the current key for this value to stay consistent // with Dictionary<TKey, TValue> which does not alter // the key if it exists. TKey oldKey = valuesToKeys [oldValue]; keysToValues [oldKey] = value; valuesToKeys.Remove (oldValue); valuesToKeys [value] = oldKey; } else { keysToValues [key] = value; valuesToKeys [value] = key; } } } public int Count { get { return keysToValues.Count; } } bool ICollection<KeyValuePair<TKey, TValue>>.IsReadOnly { get { return false; } } public void Add (TKey key, TValue value) { if (key == null) throw new ArgumentNullException ("key"); if (value == null) throw new ArgumentNullException ("value"); if (keysToValues.ContainsKey (key)) throw new ArgumentException ("Key already exists", "key"); if (valuesToKeys.ContainsKey (value)) throw new ArgumentException ("Value already exists", "value"); keysToValues.Add (key, value); valuesToKeys.Add (value, key); } public void Replace (TKey key, TValue value) { if (key == null) throw new ArgumentNullException ("key"); if (value == null) throw new ArgumentNullException ("value"); // replaces a key value pair, if the key or value already exists those mappings will be replaced. // e.g. you have; a -> b, b -> a; c -> d, d -> c // you add the mapping; a -> d, d -> a // this will remove both of the original mappings Remove (key); inverse.Remove (value); Add (key, value); } void ICollection<KeyValuePair<TKey, TValue>>.Add (KeyValuePair<TKey, TValue> item) { Add (item.Key, item.Value); } public bool Remove (TKey key) { if (key == null) throw new ArgumentNullException ("key"); TValue value; if (keysToValues.TryGetValue (key, out value)) { keysToValues.Remove (key); valuesToKeys.Remove (value); return true; } else { return false; } } bool ICollection<KeyValuePair<TKey, TValue>>.Remove (KeyValuePair<TKey, TValue> item) { bool removed = ((ICollection<KeyValuePair<TKey, TValue>>) keysToValues).Remove (item); if (removed) valuesToKeys.Remove (item.Value); return removed; } public void Clear () { keysToValues.Clear (); valuesToKeys.Clear (); } private bool ValueBelongsToOtherKey (TKey key, TValue value) { TKey otherKey; if (valuesToKeys.TryGetValue (value, out otherKey)) // if the keys are not equal the value belongs to another key return !keyComparer.Equals (key, otherKey); else // value doesn't exist in map, thus it cannot belong to another key return false; } }}Original source and tests on github.
原始资源和github上的测试。