Possible bug in ASP.NET MVC with form values being replaced

Question

I appear to be having a problem with ASP.NET MVC in that, if I have more than one form on a page which uses the same name in each one, but as different types (radio/hidden/e

Answer 1

Example to reproduce the "design problem", and a possible workaroud. There is no workaround for the 3 hours lost trying to find the "bug" though ... Note that this "design" is still in ASP.NET MVC 2.0 RTM.

    [HttpPost]
    public ActionResult ProductEditSave(ProductModel product)
    {
        //Change product name from what was submitted by the form
        product.Name += " (user set)";

        //MVC Helpers are using, to find the value to render, these dictionnaries in this order: 
        //1) ModelState 2) ViewData 3) Value
        //This means MVC won't render values modified by this code, but the original values posted to this controller.
        //Here we simply don't want to render ModelState values.
        ModelState.Clear(); //Possible workaround which works. You loose binding errors information though...  => Instead you could replace HtmlHelpers by HTML input for the specific inputs you are modifying in this method.
        return View("ProductEditForm", product);
    }

If your form originally contains this: <%= Html.HiddenFor( m => m.ProductId ) %>

If the original value of "Name" (when the form was rendered) is "dummy", after the form is submitted you expect to see "dummy (user set)" rendered. Without ModelState.Clear() you'll still see "dummy" !!!!!!

Correct workaround:

I feel this is not a good design at all, as every mvc form developer needs to keep that in mind.