add runat="server" (from the html view) as a property of your hidden field, it will continue to work as a hidden field and it will allow you to read its value in the code behind. It might have a different way to solve this issue but this worked for me. Let me know if it works for you.
I need to POST To A Different Site in asp.net (vb.net) after users enter required data filds in a form. Specifying action (containing the URL of the site) and the target (_blank) does not help, it opens my site again.
Fields were identified as requested by the target site according to a sample HTML form I found. I also tryed with plain HTML input objects an a plain HTML form and it worked, since I'm inheriting from a base form class, this will not work.
Like I said, I tryed using a PLAIN HTML form and it worked but this will prevent the rest of the objects in the form to work, besides I'm inheriting the form from a form base class and this won't work either .
Can I have a ASP.NET form object and a PLAIN HTML form at the same time? I would wrap any object inside the ASP.NET form and the 2 other fields inside the HTML form.