Where is asp.net mvc3 controller parameter coming from?

[leo8978]

I am relatively new to MVC3 and had a question about a parameter in a controller.I have a controller that takes an id\[code\]public ActionResult ChooseItem(string id) ...\[/code\]This controller's view creates a form, and when the user submits the form it posts to this controller\[code\][HttpPost] public ActionResult ChooseApp(string id, string itemID)...\[/code\]The strange thing is, even though I do not have a hidden variable that stores \[code\]id\[/code\] in the view that is POSTing to this control, the id parameter is set correctly. This is actually a good thing, but I don't understand where the value is coming from. I have examined the POST values in Chrome dev tools and there is not an id in the form values that are POSTed. What is setting the id value correctly?