[Solved] MVC Menu does NOT work correctly with MVC4

[Peter Shaw]

Hi All,

The Telerik MVC menu component does not work correctly with MVC4, please let me state before we go any further, Iv'e gone through all the related posts I can find in the 'Menus' forum and downloaded the samples provided by Telerik staff and I have been able to reproduce the same issue in all of them.

I do also believe that I have a solution, but this will require Telerik to make changes to the MVC Menu's code and re-release.

Starting at the top

I have an MVC 4 application that serves my local network, this application is called 'Intranet'.

Within this application some users have their own area's.

When using route value dictionaries in the user areas, to create custom menus using the shared functionality in the root of the application, the MVC Menu control ignores the area value, then proceeds to throw an 'Object reference not set to an instance of an object


Within the views of these areas, menus can vary from page to page, depending on the page being viewed.

In the root of the application there is some shared functionality, namely controllers and views to facilitate logging on / off the system.

When using route value dictionaries in the user areas, to create custom menus using the shared functionality in the root of the application, the MVC Menu control ignores the area value, then proceeds to throw an 'Object reference not set to an instance of an object' exception upon accessing the page, due to the fact that in cannot find the controller it wants in the area that it is in.

A similar post in the telerik forum here ( http://www.telerik.com/community/forums/aspnet-mvc/menu/areas-in-mvc2.aspx ) which suggests using an empty area name when referencing controllers in the root of the application, and even following the advice in the above post this does not work.

The Implementation

The application is currently laid out as follows:

Areas
  ----> Sam
       ----> Controllers
       ----> Models
       ----> Views
            ----> Home
Controllers
Models
Views
  ----> Account
  ----> Home
  ----> Shared

As you can see the 'Sam' area has it's own controllers, model's & views folder as expected, and we also have the standard controllers, model's & views folders in the root of the app.

in 'Areas->Sam->Views->Home' is the following razor file called 'index.cshtml'

@using Telerik.Web.Mvc.UI

@{
    ViewBag.Title = "Intranet | Sams Portal";
}


<h2>Sams Portal</h2>
<p>Hello Sam this is where all your tools will appear</p>


@section menu
{


  @(Html.Telerik().Menu()
    .Name("menu")
    .Items(menu =>
    {
      menu.Add().Text("Home").Action("Index", "Home");
      menu.Add().Text("Logout").Action("Logout", "Account", new { area = "" });
    }))


}



As you can see, I have 2 options on the menu, home which as expected resolves to '/sam/' and correctly displays the above file, the second one however causes the afore mentioned 'Null reference exception' when browsing to the page '/sam/' which looking at the code, and seeing that it is using the correct route value dictionary to refer to the root of the app, should not happen.

If I comment the line out in the menu that creates that link, then everything works fine, so I know that it's the MVC Menu throwing the exception.

Another post in the this forum suggested that this is a common problem with all action link types, and that none of them render correctly with MVC Areas, this is not true as I can create a link to the exact 'Logout' controller I need using the following:

@Html.ActionLink("Logout","Logout", new { area = "", controller = "Account"})

This renders the link absolutely correctly, and as expected, but this option CANNOT be used with the MVC Menu as there is NO override that allows it, I have no choice in the menu but to use 'Action(string, string, string, RouteValueDictionary), also note that the action link way does not attempt to validate if the controller exists, and consequently throw said exception if it does not.

I believe that 2 things are required to fix this:

1) If Telerik where to provide the same functionality and overrides in the construction of the action parameter for the menu components as already exists in the standard action & route link calls that developers are used to, then problems like this could be resolved more easily.

2) Telerik should not prevent the view from rendering by throwing the exception seen, in my honest opinion it's far better to mirror the same behaviour that is seen in existing razor code, and simply not draw a given menu item if the controller does not exist.  There are methods in the MVC Helpers that will behave in this fashion if asked to render things like links that don't exist, as way of an example the standard 'Html.ActionLink' call will still attempt to render a link if an action does not exist, granted, it will go no where and cause a 404 when clicked, but to most developers this is better than throwing a 'Null Reference' and leaving them scratching their head with an entire view that does not render at all.

[Georgi Krustev]

Hello Peter,

 
The issue related with the "Object reference not set to an instance of an object" exception
is a known bug, which is already fixed in the latest internal build of Telerik Extensions for ASP.NET MVC. Please note that internal builds are available only to the paid customers. The next official release of the extensions, which non-paid users can download, will include the fix.

Regards,
Georgi Krustev
the Telerik team

[Peter Shaw]

Great stuff, thanks for that guys.

Do you have any idea on when the new version will be released?

Regards

Peter

[Georgi Krustev]

Hello Peter,

 
The next official release of Telerik Extensions for ASP.NET MVC is the Q3 release, which is scheduled for the October 2012. You can read more for the future of the Telerik Extensions for ASP.NET MVC here. As a workaround you can turn off the security trimming of the menu.

You can try the next release of Kendo UI for ASP.NET MVC (scheduled for the second week of July), which will have this fixed.

Kind regards,
Georgi Krustev
the Telerik team

[Peter Shaw]

Fantastic, will do, so my Last Question:

" As a workaround you can turn off the security trimming of the menu. "

How do I do that, I don't recall seeing it mentioned anywhere in the documentation?

[JFoulk]

I'm guessing...

menu().SecurityTrimming(false)

???

[Adrian Zhao]

Hi Georgi:

We are paid customer and where can I get the internal build since I have the same problem.

By the way, when are you going to release MVC 4 project template for Visual  Studio 2012 RC? 

Thanks,
Adrian

[Peter Shaw]

Thanks I'll try that.

[Andrey]

Hi Adrian,
You will need to login to www.telerik.com. Hence you can check the latest internal builds from the top menu "Manage Products" -> "Latest internal builds". This link will navigate to the page, where you can select the product (Telerik Extensions for ASP.NET MVC) and the major version (Q2 2012).

About MVC 4 templates in Visual Studio 2012 - those are already available. I would recommend making sure you have our latest VSExtensions installed. You can do that using the following steps:

1. Open the Visual Studio Extension Manager (Tools -> Extensions and Updates...)
2. Select the Updates tab
3. Update all of the Telerik VSExtensions you use

Regards,
Andrey
the Telerik team