Minimal-locking thread-safe hashtable?

Are there any available implementations of a Hashtable that provide thread safety with minimal locking in .NET? Or in another language that can be ported to .NET?

We're looking for something in between using a BCL Dictionary<,> class with lock() and a distributed caching开发者_如何学JAVA application like memcached or Velocity.

The intended use is for a cache with thousands of readers reading out immutable values based on keys (either numbers or guids, we haven't decided which yet). There will be far less writers, possibly only one.

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Starting in .Net 4.0 there is ConcurrentDictionary. This is a hashtable style structure meant for high performance use between multiple threads.

Details on it's use and implementation can be found here:

• http://blogs.msdn.com/pfxteam/archive/2010/01/08/9945809.aspx

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In What's the best way of implementing a thread-safe Dictionary? Brian Rudolf shares a link to a thread-safe dictionary that uses ReaderWriterLockSlim: http://devplanet.com/blogs/brianr/archive/2008/09/26/thread-safe-dictionary-in-net.aspx.

You might also look at the Synchronized Hashtable: http://msdn.microsoft.com/en-us/library/system.collections.hashtable.aspx.