Partial view - avoiding nested forms - asp.net-mvc

Question

View
#using (Html.BeginForm())
{
...form elements
#Html.Action("PartialView")
}
PartialView
if (something) {
<input type="submit" value="Submit" />
} else {
#using (Html.BeginForm())
{
<input type="submit" value="Submit" />
}
Can anybody suggest a way around the above problem?
If the PartialView if statement returns false, I end up with nested forms. I can move the form close bracket within the partial view to avoid nesting the forms and the page renders correctly but this upsets visual studio because it expects to see the close bracket within the view. Does that matter?
Edit:
Based on Chris's comments, is the below modification a better approach? i.e. One form with two submit buttons that call different code within the same action method?
PartialView
if (something) {
<input type="submit" name="btn" value="Submit1" />
} else {
<input type="submit" name="btn" value="Submit2" />
}
Controller
[HttpPost]
public ActionResult Index()
{
if (btn == "Submit1") {
...do a thing
} else {
...do another thing
};
}

Answer 1

<form> tag inside another <form> is not a valid HTML
Refer W3c Spec
Workaround available
http://blog.avirtualhome.com/how-to-create-nested-forms/

Answer 2

I run into the same problem, and came up with a helper that really solves it.
/**
* Ensure consequent calls to Html.BeginForm are ignored. This is particularly useful
* on reusable nested components where both a parent and a child begin a form.
* When nested, the child form shouldn't be printed.
*/
public static class SingleFormExtensions
{
public static IDisposable BeginSingleForm(this HtmlHelper html)
{
return new SingleForm(html);
}
public class SingleForm: IDisposable
{
// The form, if it was needed
private MvcForm _form;
public SingleForm(HtmlHelper html)
{
// single per http request
if (!HttpContext.Current.Items.Contains(typeof(SingleForm).FullName))
{
_form = html.BeginForm();
HttpContext.Current.Items[typeof(SingleForm).FullName] = true; // we need the key added, value is a dummy
}
}
public void Dispose()
{
// close the form if it was opened
if (_form != null)
{
_form.EndForm();
HttpContext.Current.Items.Remove(typeof(SingleForm).FullName);
}
}
}
}
To use it, include the namespace of the extension and do #Html.BeginSingleForm( everywhere you want. Not just inside nested views, but also in the parent.
Points of interest: There is a need to save whether or not the form has opened earlier. We can't have a static or static per thread variable ThreadStatic, as this might be used by many Asp.Net threads. The only single-threaded and per-http-request place to add a variable is the HttpContext.Current.Items dictionary.
There is no limitation to the number of submit buttons. The problem is the nested form elements. To avoid having multiple submit buttons you can either hide them using jquery, or extend this helper to automatically add a submit button at the end.