All fileds of a form are submitted on POST, indifferent of the type, thus also the hidden ones. Check your http traffic to see, if the field is part of the POST body. Use Fiddler or the network inspectors in IE10+ or Chrome. Firefox has also an inspector as add-in. It should be there, if not, your html form is not valid. On controller side you better use mapping by adding the necessary action method parameter, or model binding. Still,
this works too[
^]. But not in the controller constructor!
And simply debug your action method and see what's in the Request variable.