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copied!<p>If you only have 2 threads accessing this resource (ie concurrent reads are not required), then the simplest (and one of the quickest) would just be to use the <code>lock</code> keyword:</p> <pre><code>public class QuoteStore { private readonly List<Quote> _quotes = new List<Quote>(); private readonly object _mutex = new object(); public ReadOnlyCollection<Quote> GetQuotes() { lock (_mutex) { return _quotes.ToReadOnly(); } } public void AddQuote() { lock (_mutex) { _quotes.Add(quote); } } } </code></pre> <p>If however concurrent reads are required this would be a good fit for <a href="http://msdn.microsoft.com/en-us/library/system.threading.readerwriterlockslim.aspx" rel="nofollow">the ReaderWriterLockSlim class</a>. You can acquire the read lock when copying data and the write lock when writing data eg:</p> <pre><code>public class QuoteStore : IDisposable { private readonly ReaderWriterLockSlim _mutex = new ReaderWriterLockSlim(); private readonly List<Quote> _quotes = new List<Quote>(); public ReadOnlyCollection<Quote> GetQuotes() { _mutex.EnterReadLock(); try { return _quotes.ToReadOnly(); } finally { _mutex.ExitReadLock(); } } public void AddQuote() { _mutex.EnterWriteLock(); try { _quotes.Add(quote); } finally { _mutex.ExitWriteLock(); } } public void Dispose() { _mutex.Dispose(); } } </code></pre> <p>Or if you are using .Net 4 or above there are many wonderful concurrently modifiable collections in <a href="http://msdn.microsoft.com/en-us/library/dd287108.aspx" rel="nofollow">the System.Collections.Concurrent namespace</a> which you could probably use without any problem (they are lock free objects and are generally very quick - and <a href="http://blogs.msdn.com/b/pfxteam/archive/2011/11/08/10235147.aspx" rel="nofollow">some performance enhancements are coming in .Net 4.5 too</a>!). </p>

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