title: Lookup function works, until deployment
body: <p>I'm working with Visual Studio Reporting Services 2008, and I've come across an irritating problem. I have a cell in a table that uses a Lookup from one dataset to find the information to display in another. The code is as follows:</p>
  
  <pre class="lang-vb prettyprint-override"><code>=Lookup(Fields!place_id.Value,
          Fields!id.Value,
          Fields!name.Value,
          "Centres")
  </code></pre>
  
  <p>The <code>place_id</code> and <code>id</code> are from one dataset (Dataset1) and the other is from the dataset "Centres". This works fine in the preview, but not after deployment. When I try to deploy, I get an error message (where textbox22 is the cell in question):</p>
  
  <blockquote>
    <p>The Value expression for the text box ‘Textbox22’ refers to the field ‘name’.  Report item expressions can only refer to fields within the current dataset scope or, if inside an aggregate, the specified dataset scope.</p>
  </blockquote>
  
  <p>Surely, by having "Centres" there in the expression, that <em>is</em> the specified scope. Any ideas?</p>