Bem.Collections.WeakDictionary 1.0.1

Bem.Collections.WeakDictionary

Overview

A thread-safe dictionary implementation that stores values with weekly referenced keys. See WeakReference<T>.
Once a key is not strong-referenced anymore the entry will be removed automatically from WeakDictionary<TKey,TValue>.
This collection can be used for similar purposes as ConditionalWeakTable<TKey,TValue> except that WeakDictionary<TKey,TValue> can accept custom IEqualityComparer<T> instance for key comparison. ConditionalWeakTable<TKey,TValue> can only compare keys by reference no matter if GetHashCode() and Equals() methods are overridden or not.
Internally WeakDictionary<TKey,TValue> uses a combination of Dictionary<TKey,TValue> and ConditionalWeakTable<TKey,TValue> types to manage entries.

Usage

Use the same way as a generic Dictionary<TKey,TValue>.

var dictionary = new WeakDictionary<MyReferenceType, AnyType>(optionalEqualityComparer);

Note that WeakDictionary<TKey,TValue> implements only IDictionary<TKey,TValue>, IEnumerable<T> and IEnumerable interfaces.
Note that TKey must be reference type, but TValue can be anything you want.
Also note that TValue by default is not stored as a WeakReference<T>. Therefore if key and value reference the same object GC can not collect the instance!
Consider this if you plan to use WeakDictionary<TKey,TValue> as a HashSet<T> and avoid using the same instance for key and value.

Use Cases

The single use case of this library is when you need to use a custom IEqualityComparer<T> for the weakly referenced keys. If this is not a requirement use the ConditionalWeakTable<TKey,Tvalue> instead.

More info on GitHub