Bi-directional Dictionary implementation - Ran Wahle's blog

There were several times, during my short development career, that I’ve used Dictionary<TKey, TValue>. It may not be on most cases, but I’m sure in many of them, I needed to find a dictionary item by it’s value whereas the dictionary’s values were unique as well as it’s keys. This led me to the motivation of developing a dictionary that will support bi-directional access.