title: ReportViewer error on debugging
body: <p>I am working on some code a previous developer built at my company trying to add a <code>ReportViewer</code> to an ASP.NET C# page.  When I begin debugging I get the following.</p>
  
  <pre><code> Parser Error Message: The base class includes the field 'ReportViewer1', but its type 
  (Microsoft.Reporting.WebForms.ReportViewer) is not compatible with the type of control 
  (Microsoft.Reporting.WebForms.ReportViewer).
  </code></pre>
  
  <p>I read some articles suggesting my reference might be old.  I am referencing <code>Microsoft.ReportViewer.WebForms 9.0.0.0.</code></p>
  
  <p>I have a <code>ReportViewer</code> in a different page, same project, that is working.  When I change my reference to <code>WebForms 10.0.0.0</code> it breaks with a similar message.  In order to get it working again I have to change back to <code>9.0.0.0</code> and put back my <code>web.config</code> from before I made this change.</p>
  
  <p>To get all ReportViewers to work do I need to be on 9.0.0.0 or 10.0.0.0 and do I need to make changes to the web.config?</p>
  
  <p>Here are the two report viewers.  I don't see anything pertinent that is different with them.</p>
  
  <p>Working today under 9.0.0.0 in page1.aspx</p>
  
  <pre><code>&lt;rsweb:ReportViewer ID="ReportViewer1" runat="server" Height="515px" ProcessingMode="Remote" Width="100%" Visible="false"&gt;
      &lt;ServerReport ReportServerUrl="http://servername/reportserver" /&gt;
  &lt;/rsweb:ReportViewer&gt;
  </code></pre>
  
  <p>Not working under 9.0.0.0 or 10.0.0.0 in page2.aspx</p>
  
  <pre><code>&lt;rsweb:ReportViewer ID="ReportViewer1" runat="server" Font-Names="Verdana" 
      Font-Size="8pt" ProcessingMode="Remote" 
      WaitMessageFont-Names="Verdana" WaitMessageFont-Size="14pt"&gt;
      &lt;ServerReport ReportServerUrl="http://servername/reportserver" /&gt;       
  &lt;/rsweb:ReportViewer&gt;
  </code></pre>