title: SSRS Switch text box
body: <p>I have a requirement where I have a document called 'F' 'R' and 'C' (@DocNumber)
  When I type this into my report, I have three fields that get populated. I want to condense this into 1 text field and create an expression to say</p>
  
  <pre><code>Iif document = 'F',
     show Fields!FRSDisplay.Value,
  Iif document = 'R',
      show Fields!RSDisplay.Value,
  Iif document = 'C',
      show Fields!CSDisplay.Value,
  NULL()
  </code></pre>