How to customize .NET 4.0's System.Runtime.Caching.ChangeMonitor

namespace CustomChangeMonitorDemo { public class ClipboardChangeMonitor : ChangeMonitor { #region Var private string _clipboardText; private Timer _timer; private string _uniqueID; #endregion

	#region Private Property
	private string m_ClipboardText
	{
		get { return _clipboardText ?? string.Empty; }
		set 
		{
			if (_clipboardText == value)
				return;

			_clipboardText = value;
			OnChanged(value);
		}
	}

	private System.Windows.Forms.Timer m_Timer 
	{
		get
		{
			return _timer ?? (_timer = new System.Windows.Forms.Timer());
		}
	} 
	#endregion


	#region Public Property
	public override string UniqueId
	{
        get { return _uniqueID ?? (_uniqueID = Guid.NewGuid().ToString()); }
	} 
	#endregion


	#region Constructor
	public ClipboardChangeMonitor()
	{
		m_Timer.Interval = 1000;
		m_Timer.Tick += m_Timer_Tick;
		m_Timer.Start();

		_clipboardText = Clipboard.GetText();

		InitializationComplete();
	}
	#endregion


	#region Protected Method
	protected override void Dispose(bool disposing)
	{
	} 
	#endregion


	#region Event Process
	void m_Timer_Tick(object sender, EventArgs e)
	{
		m_ClipboardText = Clipboard.GetText();
	}  
	#endregion
}

}

namespace CustomChangeMonitorDemo { class Program { [STAThread] static void Main(string[] args) { FileContentProvider textFile = new FileContentProvider(); Stopwatch sw = new Stopwatch(); while (true) { sw.Reset(); sw.Start(); Console.WriteLine(textFile.Content); sw.Stop(); Console.WriteLine(“Elapsed Time: {0} ms”, sw.ElapsedMilliseconds); Console.WriteLine(new string(’=’, 50)); Console.ReadLine(); Application.DoEvents(); } } }

public class FileContentProvider
{
	public String Content
	{
		get
		{
			const string CACHE_KEY = "Content";
			string content = m_Cache[CACHE_KEY] as string;
			if (content == null)
			{
				CacheItemPolicy policy = new CacheItemPolicy();
				//policy.SlidingExpiration = TimeSpan.FromMilliseconds(1500);

				var changeMonitor = new ClipboardChangeMonitor();

				policy.ChangeMonitors.Add(changeMonitor);

				content = Guid.NewGuid().ToString();
				Thread.Sleep(1000);
				m_Cache.Set(CACHE_KEY, content, policy);
			}
			return content;
		}
	}

	private ObjectCache _cache;
	private ObjectCache m_Cache
	{
		get
		{
			if (_cache == null)
				_cache = MemoryCache.Default;
			return _cache;
		}
	}
}

}

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