title: How to check if String is null
body: <p>I am wondering if there is a special method/trick to check if a <code>String</code> object is null. I know about the <a href="http://msdn.microsoft.com/en-us/library/system.string.isnullorempty.aspx" rel="noreferrer"><code>String.IsNullOrEmpty</code></a> method but I want to differentiate a <code>null</code> String from an empty String (=<code>""</code>).</p>
  
  <p>Should I simply use:</p>
  
  <pre><code>if (s == null) {
      // blah blah...
  }
  </code></pre>
  
  <p>...or is there another way?</p>