.Net Interview Question: What is Reader Writer Locks?

You may want to lock a resource only when data is being written and permit multiple clients to simultaneously read data when data is not being updated. The ReaderWriterLock class enforces exclusive access to a resource while a thread is modifying the resource, but it allows nonexclusive access when reading the resource. Reader Writer locks are a good alternative to exclusive locks that cause other threads to wait, even when those threads do not need to update data.