Issues During ASP.NET MVC Upgrade from Preview 5 to Beta?

Question

What issues or refactoring did you have to do when you upgraded from ASP.NET MVC Preview 5 to the newly released Beta version?

Answer 1

I'm about to do this myself. Here's the list of changes from the readme:

Changes Made Between CodePlex Preview 5 and Beta

• Changed the default validation messages to be more end-user friendly.
• Renamed CompositeViewEngine to AutoViewEngine.
• Added a Url property to Controller of type UrlHelper. This makes it convenient to generate routing-based URLs from within a controller.
• Added the ActionNameSelectorAttribute abstract base class, which serves as the base type for ActionNameAttribute. By inheriting from this base attribute class, you can create custom attributes that participate in action selection by name.
• Added a new ReleaseView method to IViewEngine that allows custom view engines to be notified when a view is done rendering. This is useful for cleanup or for view-pooling scenarios.
• Renamed the ControllerBuilder method DisposeController to ReleaseController to fit with the pattern that is established for view engines.
• Removed most of the methods on the HtmlHelper class, converting them to extension methods of the HtmlHelper class instead. These methods exist in a new namespace (System.Web.Mvc.Html). If you are migrating from Preview 5, you must add the following element to the namespaces section of the Web.config file: <add namespace="System.Web.Mvc.Html"/> This makes it possible for you to completely replace our helper methods with your own.
• Changed the default model binder (DefaultModelBinder) to handle complex types. The IModelBinder interface has also been changed to accept a single parameter of type ModelBindingContext.

• Added a new HttpVerbs enumeration that contains the most commonly used HTTP verbs (GET, POST, PUT, DELETE, HEAD). Also added a constructor overload to AcceptVerbsAttribute that accepts the enumeration. The enumerated values can be combined. Because it is possible to respond to HTTP verbs that are not included in the enumeration, the AcceptVerbsAttribute retains the constructor that accepts an array of strings as a parameter. For example, the following snippet shows an action method that can respond to both POST and PUT requests.

  [AcceptVerbs(HttpVerbs.Post | HttpVerbs.Put)]
  public ActionResult Update() {... }

• Modified the RadioButton helper method to ensure that every overload accepts a value. Because radio buttons are used to specify a choice from a set of possible values, specifying a value for a radio button is necessary.

• Made modifications and fixes to the default project template. This includes moving script files to a new Scripts folder. The default template uses the ModelState class to report validation errors.

• Changed action-method selection. If two action methods match a request, but only one of those has an attribute that derives from ActionMethodSelectorAttribute that matches the request, that action is invoked. In earlier releases, this scenario resulted in an exception. For example, the following two action methods are in the same controller:

  public ActionResult Edit() {
  //...
  }

  [AcceptVerbs(HttpVerbs.Post)]
  public ActionResult Edit(FormCollection form) {
  //... }

In Preview 5, a POST request for the Edit action would cause an exception, because two methods match the request. In the Beta, precedence is given to the method that matches the current request via the AcceptVerb attribute. In this example, the first method will handle any non-POST requests for the Edit action.

• Added an overload for the ViewDataDictionary.Eval method that accepts a format string.
• Removed the ViewName property from the ViewContext class.
• Added an IValueProvider interface for value providers, along with a default implementation, DefaultValueProvider. Value providers supply values that are used by the model binders when binding to a model object. The UpdateModel method of the Controller class has been updated to allow you to specify a custom value provider.

Answer 2

Issue number one: Yellow screen of death.
CS0234: The type or namespace name 'Mvc' does not exist in the namespace 'System.Web' (are you missing an assembly reference?)

Solution: I removed all references in my project and re-added them, pointing to the assemblies in program files\asp.net\asp.net mvc beta\assemblies, but that didn't solve the problem.

I had a system.web.mvc dll in the gac (no idea how). Tried to delete it. Unable to; assembly is required by one or more applications. Had to find the assembly as described here and delete the registry entry. I was then able to remove the gac's version of system.web.mvc.

This STILL didn't fix the problem. I had to RE-ADD the references AGAIN. Now its working.

---

Just to be clear!!! The beta assemblies were dropped under Program Files, while an older version of System.Web.Mvc was in the GAC.

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Answer 3

I use Autofac as my DI container. A null container exception gets thrown when trying to dispose of the container objects.

Answer 4

I experienced the same problem as Will and had to do similar things as him, including copying the dlls to the bin folder.

Now things are working in the internal vs.net server but are causing IIS7 to crash.

Ok, it turns out one of the major problems is that I missed the step to update the compilation assemblies in the web.config:

<add assembly="System.Web.Mvc, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

Answer 5

Yup, also use Autofac as DI container.

Get same issue as this guy

http://groups.google.com/group/autofac/browse_thread/thread/68aaf55581392d08

No idea if a fix is possible but cant continue until this is fixed ......

Answer 6

Disregard this... I'm a loser - it's Microsoft ASP.net in program files... not just ASP.net

Maybe this should be a second question, but I think keeping it all in one place might help.

When running the Beta installer nothing ends up changing on my PC. I don't see the folder in the Program Files folder... no assemblies are added to the GAC... even the installer gets to the last step and then hangs for around 10 minutes or so.

I've uninstalled and reinstalled a couple times now without any luck.

Anyone having a similar problem?

Answer 7

After struggling with this for most of the day, I figured I'd post my solution here. Maybe this is normal Visual Studio behavior but I never noticed it before...

On my existing project, I actually had to manually move the Beta files to the Bin folder. For whatever reason, just browsing to it with Add Reference wasn't working...

Answer 8

Html.TextBox - value now is object, not string. So, hidden errors possible (not at compile time and even not at runtime), for example I've used this overloaded method earlier Html.TextBox(string name, object htmlAttributes). Now my attrs go into textbox value.

Answer 9

About the Autofac issue. There is a thread on the autofac discussion group about the need to update the controller factory to be compatible with the Beta release of the MVC framework

http://groups.google.com/group/autofac/browse_thread/thread/68aaf55581392d08

I hope they post a new version very very soon :-)

Answer 10

When I upgraded from Preview 5 to Beta I had difficulty locating the generic overloads of ActionLink. It appears that those are not included in the main release of ASP.NET MVC but are being shipping as "futures".

I found the necessary assembly (Microsoft.Web.Mvc) @ http://www.codeplex.com/Release/ProjectReleases.aspx?ProjectName=aspnet&ReleaseId=18459

Answer 11

The problem with AutoFac has now been resolved in Revision 454 of the AutoFac code base http://code.google.com/p/autofac/issues/detail?id=86&can=1

Answer 12

Im trying to find out how the new ModelBinder works, as far as I can see it's very different, but i haven't managed to find out how it works yet..

My old looked like:

public class GuestbookEntryBinder : IModelBinder
    {
        #region IModelBinder Members

        public object GetValue(ControllerContext controllerContext, string modelName, Type modelType, ModelStateDictionary modelState)
        {
            if (modelType == typeof(GuestbookEntry))
            {
                return new GuestbookEntry
                {
                    Name = controllerContext.HttpContext.Request.Form["name"] ?? "",
                    Website = controllerContext.HttpContext.Request.Form["website"] ?? "",
                    Message = controllerContext.HttpContext.Request.Form["message"] ?? "",
                };
            }
            return null;
        }
        #endregion
    }

The new one looks like:

#region IModelBinder Members

public ModelBinderResult BindModel(ModelBindingContext bindingContext)
{
    throw new NotImplementedException();
}

#endregion

Any hints?

Answer 13

There is a breaking change in the ViewContext constructor. It has changed from:

ViewContext(ControllerContext context, string viewName, ViewDataDictionary viewData, TempDataDictionary tempData)

to:

ViewContext(ControllerContext context, IView view, ViewDataDictionary viewData, TempDataDictionary tempData)

This broke my code because I am using MvcContrib.Services.IEmailTemplateService, which takes a ViewContext in its RenderMessage method. To get an IView from the template name, I am doing the following:

var view = ViewEngines.DefaultEngine.FindView(controllerContext, viewName, null);

Not sure if this is the best practice, but it seems to work.

Answer 14

If you are using Html.Form from the futures assembly (Microsoft.Web.Mvc) you might get a name collision on the FormMethod enum. For example:

Html.Form<FooController>(c => c.Bar(), FormMethod.Post, new Hash(@class => "foobar"))

This will complain that FormMethod is an ambiguous reference between Microsoft.Web.Mvc and System.Web.Mvc. This is quite sad because IMHO BeginForm does not provide a viable option due to its lack of an override that uses a lambda expression. Your only option is to use magic strings, which resist refactoring.

The best solution, it seems, is to put the following into every view that uses FormMethod:

<%@ Import Namespace="FormMethod=Microsoft.Web.Mvc.FormMethod"%>

Ugh. Hopefully this is temporary. I expect that the futures assembly can be changed to use the enum from System.Web.Mvc. Or much better yet, hopefully they overload BeginForm to use expressions.

Answer 15

It seems that Html.Image is broken. As of preview 5 it was moved to the futures assembly. I cannot imagine why. Anyway, the error is:

Method not found: 'Void System.Web.Mvc.UrlHelper..ctor(System.Web.Mvc.ViewContext)'

The best solution I can see is to replace this:

<%=Html.Image("~/Content/Images/logo.jpg") %>

with this:

<img src="<%=Html.ResolveUrl("~/Content/Images/logo_350.jpg")%>" />

Answer 16

This is now broken:

<%=Html.TextBox("Name", new Hash(@class => "required"))%>

In Preview 5 the above would bind the value of ViewData.Model.Name to the textbox. This still works:

<%=Html.TextBox("Name")%>

But if you want to specify html attributes, you must also specify the value as follows:

<%=Html.TextBox("Name", ViewData.Model.Name, new Hash(@class => "required"))%>

Actually this is not really safe. If there is any chance ViewData.Model might be null you need to do something like this:

<%=Html.TextBox("Name", ViewData.Model == null ? null : ViewData.Model.Name, new Hash(@class => "required"))%>

This change seems counter to the Beta release notes:

"...in order to reduce overload ambiguity...the value parameter was changed from object to string for several helper methods."

The value parameter for TextBox used to be string, and it was changed to object. So to avoid ambiguities they had to remove the one overload that I use the most. :(

IMHO, every HTML helper method should have overloads that allow binding in all cases without specifying the value. Otherwise we will end up with inconsistent view code that will confuse future devs.

Answer 17

All i had to do was update the assemblies from

%ProgramFiles%\Microsoft ASP.NET\ASP.NET MVC Beta

Also get the most recent Microsoft.Web.MVC from codeplex

to update my futures assembly too.

add in 2 lines to the web.config

This one to the <assemblies> Section:

<add assembly="System.Web.Mvc, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

This one to the <namespaces> section:

<add namespace="System.Web.Mvc.Html"/>

Then i had to update all the <%using (Html.Form()) to <%using (Html.BeginForm())

On one code file i had to add the System.Web.Mvc.Html; namespace

My stuff is based on Rob Conery's MVC Storefront, so anyone using that should be able to follow the above.

Hope it helps someone out there.

Answer 18

What Will said above, except that in addition to deleting the assemblies from the GAC and re-adding the references I also had to run the Beta installer again (putting the right assemblies in the GAC this time, though I'm just using a file reference).

I suspect if I'd deleted the Preview 5 assemblies from the GAC (and I've no idea how they got in there either) before I ran the installer, everything might have been OK. Worth trying.

In the unlikely event that anyone else out there is as daft as me and working on Vista, you may not need to do the registry hacking above in order to delete the old assemblies - just run gacutil from an admin command prompt. Doh!

Answer 19

I found that updating the web.config namespaces element with the namespaces from a blank project fixed my problems. I also had to update my ModelBinders due to the interface change.