title: Filewatcher returning error. No overload matches delegate
body: <p>I've written this method which should check for file changes.</p>
  
  <pre><code>public static void watch()    
     {    
          FileSystemWatcher watcher = new FileSystemWatcher();    
          watcher.Path = ConfigurationManager.AppSettings["OpticusFileLoc"];    
          watcher.Filter = "sigtrades.xml";    
          watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite
         | NotifyFilters.FileName | NotifyFilters.DirectoryName;    
  
  
         // watcher.Created += new FileSystemEventHandler(OnChanged);
          watcher.Changed += new FileSystemEventHandler(OnChanged);
  
          watcher.EnableRaisingEvents = true;
  
      }
  </code></pre>
  
  <p>However, I get this error:
  "No overload for 'OnChanged' matches delegate 'System.IO.SystemEventHandler'</p>
  
  <p>Where am I going wrong?</p>