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asp.netvb.netweb-config

Why is the renderAllHiddenFieldsAtTopOfForm configuration setting ignored?

I'm experiencing the exact opposite problem of the poster of this question: Why isn't "renderAllHiddenFieldsAtTopOfForm" not working?

I have explicitly set renderAllHiddenFieldsAtTopOfForm to true:

<system.web>
    <pages renderAllHiddenFieldsAtTopOfForm="true" />
</system.web>

Nonetheless, the rendered output contains two distinct sections containing the system-generated hidden fields: one at the top, and one at the bottom of the form:

<div class="aspNetHidden">
    <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwULLTE4NDI1MTc3MzRkZI7H1ncHbGpdCuTIWztffomjhuKqOlUg2/NLTSuTAcPt" />
</div>

<div class="aspNetHidden">
    <input type="hidden" name="__VIEWSTATEGENERATOR" id="__VIEWSTATEGENERATOR" value="C2EE9ABB" />
    <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEdAATsr4X0euI6bC1nyD5GTh1SVvvE46VZo4PgfZC+nBCfTprQreIcKZCPCAR/ghE+h144RSSJ+WpNEsH2OOfrgDPYSZR3/cXf22QHuxsfDnv9/WdF+DPQdHKniJorPN8Mw6c=" />
</div>

Can anyone explain why this is happening?

The pertinents: This is an ASP.NET 4.5 application running under IIS 7, written in VB.NET built with Visual Studio 2013. This behavior can be observed on every page, and happens whether I remove the renderAllHiddenFieldsAtTopOfForm setting or not, or if I set its value to true or false.

Solution

  • According to Reference Source, renderAllHiddenFieldsAtTopOfForm property is only honored when InnerWriter is HttpWriter.

    Can you check if you are giving a different writer to the Render method?

    protected override void Render(System.Web.UI.HtmlTextWriter writer)
{
    base.Render(new MyHtmlTextWriter()); // <<<----
}