public override void Add(TKey key, TValue value)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
WeakReference <TKey> weakKey = new WeakKeyReference <TKey>(key, comparer);
dictionary.Add(weakKey, value);
}
protected override void SetValue(TKey key, TValue value)
{
WeakReference <TKey> weakKey = new WeakKeyReference <TKey>(key, comparer);
dictionary[weakKey] = value;
}