Question

I’m using ASP.NET MVC (1.0), Spark View Engine (1.0) and SubSonic (3.0.0.3).

I’m having some trouble getting an “Edit” view to work correctly. So, in my controller, I have the following controller action that displays the edit form view:

[AcceptVerbs(HttpVerbs.Get)]
public virtual ActionResult Edit(string name)
{
    var plot = Plot.SingleOrDefault(p => p.UserID == LoggedInUser.ID && p.UrlFriendlyName == name);
    // ViewData["plot"] = plot;
    return View(plot);
}

The form on that view posts back to the following controller action:

[AcceptVerbs(HttpVerbs.Post)]
public virtual ActionResult Edit(Plot plot)
{
    var validator = new PlotValidator();
    try
    {
        var results = validator.Validate(plot);
        if (!results.IsValid)
        {
            ...
        }
    }
}

The problem that I’m having, is that the first controller action doesn’t actually populate the form with the values from the Plot object submitted to it. The only way I can get it to populate the form is by adding the Plot to ViewData:

ViewData["plot"] = plot;

That populates the edit form, but when I edit the values, and submit it back to the second controller action listed above, it just sends back, basically a new plot with the new values, not the plot sent to the edit form with updated values.

I’m sure I’m probably just missing something simple, but I can’t seem to figure out what it is. All of the fields on my form have IDs that are prefixed with “plot.”

Anyone know/see what I’m doing wrong? Thanks.

Answer 1

I don’t know how it’s done in the Spark view engine, but in the out-of-the-box view engine that comes with ASP.NET MVC, this is done by inheriting a strongly-typed view model object in the page using a page directive, rather than using the dictionary that comes with the plain-vanilla ViewPage.

So, instead of the first line of code in the view looking like this:

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

It will look more like this:

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" 
     Inherits="System.Web.Mvc.ViewPage<HomePageViewModel>" %>

Your current controller code is expecting a strongly-typed object, but it is getting back a ViewData Dictionary instead. So no binding is occurring.

Consider reviewing the following podcast:

Exploring how to use ViewData (Strongly typed and weak typed) with Spark
http://www.dimecasts.net/Casts/CastDetails/117