title: Understanding C# proper uses of 'using' keyword
body: <p>Considering the follow code can someone explain to me why and why not to use 'using'?
  I've read about the rule of thumb with IDisposable but why is IDisposable the determining factor?</p>
  
  <pre><code>private string GetWMIProperty(string property)
  {
  string value = string.Empty;
  SelectQuery selectQuery = new SelectQuery("Win32_OperatingSystem");
  using (ManagementObjectSearcher searcher = new ManagementObjectSearcher(selectQuery))
  {
  
    foreach (ManagementObject mo in searcher.Get())
     {
       value = mo[property].ToString();
    }
  }
  return value;
  }
  </code></pre>