title: Report viewer textbox visibility expression
body: <p>I am trying to get a text box and tablix to toggle their visibility based on an expression.</p>
  
  <p>I have tried the following:</p>
  
  <pre><code>=IIF(First(Fields!Supported.Value, "FooDataSet") = "true", True, False)
  </code></pre>
  
  <p>However, this will not work for me. I'm using the 2010 version and using it in local mode.</p>
  
  <p>I also tried writing custom code to see if that would work:</p>
  
  <pre><code>Public Function ToggleVisibility(ByVal visible As string) As Boolean
    Dim isVisible As Boolean = False
    If visible = "true" Then
      isVisible = True
    End If
    Return isVisible
  End Function
  </code></pre>
  
  <p>Then I use it in the "Show or hide based on an expression" under the Visibility item in the text box and tablix properties.</p>
  
  <pre><code>=Code.ToggleVisiblity(First(Fields!Supported.Value, "FooDataSet"))
  </code></pre>
  
  <p>This also does not work for me. </p>