title: Call filter only if textbox has value
body: <p>I have the following code that filters a excel sheet</p>
  
  <pre><code>With Sheets("Inventory on Hand").Range("A1:F1")
      .AutoFilter
      Call .AutoFilter(1, UserForm1.TextBox13.Text)
      Call .AutoFilter(3, UserForm1.TextBox15.Text)
      Call .AutoFilter(4, UserForm1.TextBox14.Text)
      Call .AutoFilter(5, UserForm1.TextBox16.Text)
  End With
  </code></pre>
  
  <p>However, the problem with this is, if I were to leave <code>TextBox13</code> blank, column 1 will be filtered to rows that are blank, which is not what I want.</p>
  
  <p>How do I apply the filter to that column if and only if the corresponding textbox has a value?</p>
  
  <p>If <code>TextBox13</code> is blank, column1 should not be filtered at all.</p>