MVC - Passing Data with RedirectToAction()


Question

I'd like to take data entered in an MVC user form and display it in a different view.

The class has the following private variable:

IList<string> _pagecontent = new List<string>();

The following action accepts a FormCollection object, validates it, and passes it on to the "Preview" view as a List:

[Authorize(Roles = "Admins")]
[ValidateInput(false)]
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult UpdateContent(FormCollection collection)
{
    if (ModelState.IsValid)
    {
        string PageToInsert = collection["PageToInsert"];
        string PageHeader = collection["PageHeader"];
        string PageBody = collection["PageBody"];

        //validate, excluded...

        _pagecontent.Add(PageToInsert);
        _pagecontent.Add(PageHeader);
        _pagecontent.Add(PageBody);

    }
    return RedirectToAction("Preview", _pagecontent);
}

The Preview view has the following Page Directive for passing a strongly typed object List:

<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Template.Master" Inherits="System.Web.Mvc.ViewPage<List<string>>" %>

I would expect to be able to use the Model object to get my data, but alas I cannot. At the following line, I get an error index out of bounds exception, stating the index must be non-negative and less than the size of the collection:

<% if (Model[0].ToString() == "0") { %>

And some strange parameters have been added to the URL, as it resolves to http://localhost:1894/Admin/Preview?Capacity=4&Count=3

So I have two questions:

  1. When I call RedirectToAction and pass it my List, why is it inaccessible in the view's Model object?
  2. What is the proper way to go about doing what I'm trying to do, namely pass a collection of strings to a view for display there?
1
59
4/12/2013 9:11:56 PM

Accepted Answer

Try using TempData. It is like a single-shot session object. You put values you want into TempData, immediately redirect and get them out. There is a good writeup here: http://blogs.teamb.com/craigstuntz/2009/01/23/37947/

55
3/23/2009 3:51:19 AM

Be careful when using TempData. It works great in a single server environment but in a cloud environment it may not work as expected since you cannot guarantee that the request will hit the same machine. This happens because TempData rely on the asp.net session. But if you are using other session manager like SQL or AppFabric Cache it will work fine.


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