ansaurus

Question

What is the status of runat="server" tags in ASP.NET MVC?

Answer 1

+1 A:

They don't mean that you can't use runat="server", but rather that it not necessary to use server-side controls, generally, in MVC. If you find that you need a server-side control and are working with it in code-behind that's and indication that the application is tending back toward webforms. All of the stuff that would normally happen in your code-behind shoulo now be handled in your controller or in the view logic itself.

tvanfosson 2009-01-15 12:29:49

Hmm, then why when I create a default MVC View Master Page does it have three runat servers? It would seem that if these are not typical MVC constructs that at least the code defaults would not have them.

Edward Tanguay 2009-01-15 12:37:21

It's still using the ASP rendering engine and the ContentPlaceHolders is how you construct master pages in ASP.NET. Note that the key is "if you find yourself working with it in code-behind" -- the placeholders in MVC not addressed in the code-behind.

tvanfosson 2009-01-15 12:42:57

Answer 2

+1 A:

Just read in this tutorial:

http://www.asp.net/learn/mvc/tutorial-12-cs.aspx

that you need the

<head runat="server">

to be able to easily define the page title in your views.

Edward Tanguay 2009-01-15 12:48:33

No you don't. You can either use ViewData or use MasterPages with a contentplaceholder.

Chad Moran 2009-01-15 16:20:41

Right, I meant "automatically". Right, you can take over and do it yourself, of course.

Edward Tanguay 2009-01-15 16:27:57

No, the head runat="server" (aka HeaderControl) makes it easy to reference .css and .js files in the head section. It will rewrite the Href value. I think I'll write a blog post on this.

Haacked 2009-01-16 03:30:37

Href or Src value I meant.

Haacked 2009-01-16 03:31:23

Also works for Href and Src values elsewhere in the html document.

Peter Stephens 2009-10-05 14:45:50

Answer 3

+3 A:

If you use a runat="server" tag on ANY element, such as a DIV it will render that code as a separate method in the compiled page.

If you're converting 'legacy' code its a good idea to remove all runat tags right up front otherwise you end up in a situation where code like the following gives you an error.

<% foreach (var cat in cats) { %>
    <div runat="server">
         <span class="name"> <%= cat.name %> </span> is a
         <span class="breed"> <%= cat.breed %> </span>
    </div>
 <% } %>

This code will fail telling you some craziness about 'cat' being out of scope. Eventually when you look at the full generated code you'll see that the <div> has been generated as its whole own method - which is of course a different scope with no cats in sight.

Back for a second to the default template for an MVC application:

You'll see the current template gives you this for the head :

<head runat="server">
    <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
    <title><%= Html.Encode(ViewData["Title"]) %></title>
    <link href="../../Content/Site.css" rel="stylesheet" type="text/css" />
</head>

This left me wondering -- if we're using <%= syntax to write the title directly into the title tag - then why would we need to make it runat?

It turns out as I suspected that the codebehind for head looks for an existing value inside the title tag (which would have been output here by <%= Html.Encode(ViewData["Title"]) %>. If it finds one (which will be the case for the all sample views in the MVC template) then it won't do anything further. If no title exists (if ViewData["Title"] is null or empty) it will default to whatever is defined in your view by the Title attribute :

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/RRMaster.Master" 
Title="View Products" AutoEventWireup="true" CodeBehind="ViewProduct.aspx.cs"
Inherits="RR_MVC.Views.Products.ViewProduct" %>

In my master page I would have removed the runat='server' tag - since I dont think I'll ever want to populate my page title from the view's Title property. But I'm holding off doing this pending Phil's promised blog post on the subject - in case the runat server gives me anything useful for my CSS and JS too.

Simon_Weaver 2009-01-24 11:06:53

ansaurus

tags:

views:

answers:

What is the status of runat="server" tags in ASP.NET MVC?

related questions