#it3xl

Key objects must be immutable as long as they are used as keys in the Hashtable. When an element is added to the Hashtable, the element is placed into a bucket based on the hash code of the key. Subsequent lookups of the key use the hash code of the key to search in only one particular bucket, thus substantially reducing the number of key comparisons required to find an element. GetBucket(item. GetHashCode ()) Any object that creates a hashvalue should change the hashvalue, when the object changes, but it must not - absolutely must not - allow any changes to itself, when it is used inside a Hashtable (or any other Hash-using object, of course). So, just make GetHashCode result change, when the object data changes, and if the use of the object inside of hash using lists or objects is intended (or just possible) then make the object either immutable or create a readonly flag to use for the lifetime of a hashed list containing the object. (By the way: All of this is not C# oder

(In progress...) Big O Notation     http://stackoverflow.com/questions/2307283/what-does-olog-n-mean-exactly . The Generic Collections: System.Collections.Generic namespace     Associative Collection Classes (stores a value by a key, associates the value with the key)         useful to lookup/manipulate a collection using a key value         The Dictionary<TKey,TValue>             Best for high performance lookups.                 is the fastest class for associative lookups/inserts/deletes because it uses a hash table under the covers                 The speed of retrieval depends on the quality of the hashing algorithm of the type specified for TKey.                 the key type should correctly implement GetHashCode() and Equals() appropriately                 or you should provide an external IEqualityComparer to the dictionary on construction.                 O(1)                     insert/delete/lookup time of items in the dictionary is amortized constant ti