title: SQL Server Reporting Studio (SSRS) sorting error
body: <p>I am attempting to allow a dynamic sort on a text box on an SSRS report.  The field upon which I am trying to sort will either have an "A" or a decimal number.  I am wanting to sort the decimal numbers in descending order.  The expression I am using is:</p>
  
  <pre><code>=iif(isnumeric(Fields!CommScore.Value), (cdbl(Fields!CommScore.Value)*-1),6)
  </code></pre>
  
  <p>For the decimal number will never be larger than 5.  The error I get is:</p>
  
  <blockquote>
    <p>The sortexpression for the text box 'textbox74' contains an error.  Input string was not in a correct format.  (rsRuntimeErrorInExpression)</p>
  </blockquote>
  
  <p>I imagine this is something simple.  What am I doing wrong?</p>