Upgrade Application from Asp.Net MVC2 to MVC3

Upgrade Application from Asp.Net MVC2 to MVC3

It’s been a much long after MVC3 is been released & now it is much stable. So while working on a project, I need to upgrade my ASP.Net MVC 2 project to MVC 3.

ASP.Net MVC 3 can be installed side by side ASP.Net MVC 2 on you PC, which gives you flexibility in choosing when to upgrade an MVC2 application to MVC3. It is been very easy to upgrade the project to MVC3. We just need to follow following steps

  • Remove all references of System.Web.Mvc from each project in solution.
  • Now add a reference for System.Web.Mvc 3.0 to each of the project in the solution.
  • Also add a reference of System.Web.Helpers 2.0 to web project.
  • Also add a reference of System.Web.WebPages 2.0 to web project.
  • Go to views folder & open the Web.Config file & replace Version = 2.0.0.0 with version 3.0.0.0
  • Also add following code  to this Web.Config

  • Open the root Web.Config file & replace all references of “System.Web.Mvc 2.0.0.0” with “System.Web.Mvc 3.0.0.0”.
  • Now in appSettings add following keys

  • Now we need to make sure our system.web->pages->namespaces tag contains following entries

  • In the system.web->compilation->assemblies we should have following entries

  • Finally under the configuration -> runtime section put following code

  • And lastly add following javascript on your master pages, you need to add this javascript file to Scripts folder.  We need to get this file from any asp.net mvc3 project & paste it in the scripts folder. Also it is recommended you replace the old javascript files such as MicrosoftAjax.js, MicrosoftMvcAjax.js & MicrosoftMvcValidation.js.

Yuhu……………! Here we are. Now just compile & run your code. Now it will run on MVC3. Also we need to make sure we are targeting .net Framework 4.0 while upgrading the MVC2 application to MVC3.

Also there is a tool available to upgrade the MVC2 to MVC3. Here is a link to the tool

http://weblogs.asp.net/leftslipper/archive/2010/07/28/migrating-asp-net-mvc-2-applications-to-asp-net-mvc-3-preview-1.aspx

Cheers…..!

You can find the source code here.

ViewModels in ASP.Net MVC

The MVC architecture is all about separating the various layers of the applications in some logical parts. But this separation enforces some of the constraints on developers such as how to pass data from Controller to View. There are various ways to send those data to View such as using ViewData, ViewBag or TempData, the other ways is passing this data through ViewModels.

The view models group one or more entities or properties into one logical object which can be consumed by Views in order to render the contents on the View. The purpose of the View Models is to group all the necessary information required to render a view at a single place. This enforces a clear separation of Concerns, putting the data manipulation & domain entities away from the Controller & View. Using view models helps to create a good & maintainable code. Along with maintainable code, View Models are very beneficial in following cases

  1. Group all drop down related entities at a single place
  2. Master details records
  3. Pagination
  4. Dashboard details
  5. CRUD operations in which forms involves lot more controls

Although, from the above discussion it seems to be a more complex concept what View Model is, but actually it’s not. A view model is a simple C#/ VB.Net class, which contains some properties; those may involve primitive data type properties, or an entity or a set of entity.

Let’s create a ViewModel for following screen

The screen contains a text box for Name field & a drop down list for State. So ideally View Model should contain 2 properties 1 for Name & other for text box. So while rendering a view the ViewModel should be

This class will serve as a view Model when the view is rendered. So the controller will contain following code to render this form.

The above code will return a new form with State drop down list filled with 1 value NY. If we look at the AccountRegistrationGetViewModel carefully, you may notice [Required] attribute. This is one of the Data Annotations attribute supported by ASP.Net. They help us to validate the input data.

Now let’s create a view

It will generate a View which will contain following markup

But after validations user should be able to view the errors also we should accept these values at the Action Methods into a ViewModel. So let’s design that ViewModel.

So now when data is posted to the server in a Controller, we should catch this data in AccountRegistrationPostViewModel  . Also In order to show errors we need to add a property, as follows.

So our controller method will be So if validations are exploited these will be shown to user as below.

                 This is how we can use ViewModels. Initially it may look complex to create separate view Model for each function but later when it come to maintain the code, you will find it very very easy to fix the changes rather than striking you head on hardcoded strings.

You can find the source here.