title: Show All if parameter is null Crystal Reports
body: <p>Hi everyone I use Crystal Reports with Visual Studio 2010 and have the following issue that I can't seem to solve. I have a parameter called name, and I make it so a user chooses from a drop down list of employee names.  It is an optional parameter so the user can select nothing in which case I would like the report to show ALL the employees except for the rows that have field Employee name empty. Now I think I got the second part of it down, because I put a formula in the detail section that seems to hide all the empty employees. The problem is that if I leave the parameter unselected the report ONLY shows rows with field Employee name empty. I created a formula like so:</p>
  
  <pre><code>if not (hasvalue(({?Zaduzioc}))) then True 
  
      else if  
      hasvalue({?Zaduzioc})  then  
      {Inventar_Model_ReportClass.ImeZaduzioca} in {?Zaduzioc} and
      {Inventar_Model_ReportClass.Status} = "Aktivno"
  </code></pre>
  
  <p>Now this exact same formula works for me if I use it with a different report and parameter but that parameter has no empty values so I'm guessing it equates to something like if there are empty values show only those rows if not show everything.
  The problem is I can't figure out how to tell it to show everything.</p>
  
  <p>Any help would be greatly appreciated.</p>