title: What is vbNullString, How it use?
body: <p>What's difference between</p>
  
  <pre><code>Len(Me.txtStartDate.Value &amp; vbNullString) = 0
  </code></pre>
  
  <p>and</p>
  
  <pre><code>Len(Me.txtStartDate.Value) = 0
  </code></pre>