title: ClientScriptManager.RegisterForEventValidation with HiddenField
body: <p>I am trying to use to use ClientScriptManager.RegisterForEventValidation to register a hidden field and value that I am adding with ClientScriptManager.RegisterHiddenField.  I doing this during the Render event.  I get no error, but ASP.NET 2.0 does not appear to be validating the field.  I can change the value or delete the entire field clientside using Firefox and Firebug, and ASP.NET will not throw an error like it should.</p>
  
  <p>Sample code from a custom Page class:</p>
  
  <pre><code>protected override void Render(HtmlTextWriter writer)
  {
      ClientScript.RegisterHiddenField("stuff", "things");
      ClientScript.RegisterForEventValidation("stuff", "things");
      base.Render(writer);
  }
  </code></pre>
  
  <p>The hidden field is added to the page, but ASP.NET does not validate the field or value on postback.  What am I missing?</p>