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ASP.NET MVC C#: Object reference errors when going to view record details

Answer 1

+1 A:

In your Details action method on the controller you are not passing the model back to the view.

public ActionResult Details(int id)
{
    // get model object

    return View(//pass model object to view here);
}

aherrick 2009-07-31 02:48:49

Answer 2

A:

Your problem is in


return View(_entities.conversation.ToList());

Your View is simply your page. The View() normally is the path of the page you want to display. If you pass it without parameters ASP will get the default route based on your controller, In this case it will be redirected to Home/Index.aspx or Default.aspx depending on your routing options.

If you want to pass data to your view, you should use the ViewData hash. That hash is available on the controller and on the page side.

Ex:



Controller Code:

public ActionResult Index()
    {
        List<string> li = new List<string>();
        li.Add("test");
        ViewData["myList"] = li;
        return View();
    }

Page Code:

<div>
<%
   List<string> li = (List<string>)ViewData["myList"];
   foreach(string str in li)
   {
%>
    <p><%= str %></p>
<%
}
%>
</div>

Freddy 2009-07-31 02:49:06

Answer 3

+1 A:

It doesn't look like you're passing any data to the Details view:

public ActionResult Details(int id)
{
   return View();
}

Retrieve your model class from your repository and pass it to the view:

return View(conversation);

krohrbaugh 2009-07-31 02:50:10

Answer 4

A:

Thanks everyone for that superquick help, and those hints pointed me in the right direction. I wrongly assumed that the HomeController would have been smart enough to determine exactly what I wanted it to display after creating the view.

Those clues lead me to: http://www.asp.net/learn/MVC/tutorial-26-cs.aspx

Which after some reading gave me the answers I sought.

Here's the specific part of HomeController.CS which shows how I got it working:

 // GET: /Home/Details/5

    public ActionResult Details(int id)
    {
        var conversationToView = (from c in _entities.conversation
                                  where c.conversation_id == id
                                  select c).FirstOrDefault();
        return View(conversationToView);
    }

As aherrick noted, I was not passing the model back. conversationToView grabs the ID of the record who's details you wish to view, and passes that information to the return view action to retreive the desired result.

At the same time, I was also able to get the answer on how to perform an edit properly as well from the tutorial I found thanks to the above feedback. It's still not submitting edited information, but one step at a time.

Once again, thanks to everyone who responded so dammed quickly to this. It's been racking my brains for days.

thewinchester 2009-07-31 03:31:58

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ASP.NET MVC C#: Object reference errors when going to view record details

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