KeyedCollection<TKey, TItem>.Contains Method (TKey)
Determines whether the collection contains an element with the specified key.
Assembly: mscorlib (in mscorlib.dll)
If the KeyedCollection<TKey, TItem> has a lookup dictionary, key is used to search the dictionary. If there is no lookup dictionary, the key of each element is extracted using the GetKeyForItem method and compared with the specified key.
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