Question

Is it possible to return a string from controller upon a form submission ?

Answer 1

You can, as Darin suggest, return Content(string);
There are also other possibilities such as

[HttpPost]
public ActionResult Index(FormCollection form) {
    /*
      return Json(json);
      return View;
      return PartialView;
    */
}

If you return something other than an action result it will automatically be wrapped in a ContentResult.

[HttpPost]
public ContentResult Index(FormCollection form) {
    /*
      return Content(string); 
      return File(bytes, contentType);
      return DateTime.Now;
      return 2;
    */
}