How to RedirectToAction in ASP.NET MVC without losing request data


Question

Using ASP.NET MVC there are situations (such as form submission) that may require a RedirectToAction.

One such situation is when you encounter validation errors after a form submission and need to redirect back to the form, but would like the URL to reflect the URL of the form, not the action page it submits to.

As I require the form to contain the originally POSTed data, for user convenience, as well as validation purposes, how can I pass the data through the RedirectToAction()? If I use the viewData parameter, my POST parameters will be changed to GET parameters.

1
120
8/15/2016 2:03:16 AM

Accepted Answer

The solution is to use the TempData property to store the desired Request components.

For instance:

public ActionResult Send()
{
    TempData["form"] = Request.Form;
    return this.RedirectToAction(a => a.Form());
}

Then in your "Form" action you can go:

public ActionResult Form()
{
    /* Declare viewData etc. */

    if (TempData["form"] != null)
    {
        /* Cast TempData["form"] to 
        System.Collections.Specialized.NameValueCollection 
        and use it */
    }

    return View("Form", viewData);
}
79
2/7/2016 12:59:36 AM

Keep in mind that TempData stores the form collection in session. If you don't like that behavior, you can implement the new ITempDataProvider interface and use some other mechanism for storing temp data. I wouldn't do that unless you know for a fact (via measurement and profiling) that the use of Session state is hurting you.


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