With the introduction of ASP.NET MVC, the traditional ‘Control’ model of GUI component development went away. Instead it was replaced with the more Web 2.0 style JavaScript and jQuery plugin extensibility model. Nevertheless, adding incremental features to existing HTML components was always required and towards this end Microsoft introduced the HtmlHelper and helper extensions. Helper extensions are .NET extension methods that return a string. Typically, this string is formatted HTML content.

In our sample today we create an extension that renders a bar chart on HTML5 Canvas. It can be bound to a data source from the server side or be assigned data source from the client side.

Building a Html Helper Extension

Html Helper extensions are easy to build. Just follow the steps below to create our helper skeleton.

Step 1: We start with an MVC project and pick the Blank template.

Note we could pick a class library project template too and add package references as follows (via the Nuget package manager as follows)

a. PM> install-package Microsoft.AspNet.Mvc
b. Add reference to System.Web.dll from the ‘Add References’ dialog for the project

Step 2: Add a static class called ChartExtensions. Extension methods, by design, have to be defined in Static classes.

Step 3: Next add a static method Chart whose first parameters is this HtmlHelper and subsequent parameters are values required for rendering the chart.



a. The dataSource is a list of integer arrays. For the example we have assumed a two dimensional array would be provided as a data source. We can make it more sophisticated by making it an array of objects and binding to different properties of the object.
b. xTitle: The text to be displayed on the x-axis.
c. yTitle: The text to be displayed on the y-axis.

Step 4: Next we setup two methods, one to convert the dataSource to JSON and the other to generate the required HTML.



a. The GetDataSourceFromIntArray method uses the System.Web.Helpers’ Json static class to convert the input data source into a Json String. This string is assigned to a variable called arrDataSource and the whole string is returned.
b. The SetupHtml method implements the rendering logic

Step 5: Using TagBuilder to build the Html: ASP.NET provides us with the TagBuilder class that has helper methods to help create HTML elements easily. We use the TagBuilder to create our HTML layout as follows

<div>
<canvas …> … </canvas>
<script …> … </script>
<noscript> … </noscript>
</div>

The actual code is as follows


a. As seen above, the TagBuilder object has an Attributes collection to which we can add the HTML attributes we need. To set text between the opening tag and closing tag, we use the SetInnerText. However unlike an XmlTextWriter, we can’t nest tags. To nest tags we simply assign the string representation of the TagBuilder to the InnerHtml of the parent TagBuilder. So the ‘container’ Tag Builder has the <div> that encapsulates the Canvas and the Script tags.
b. We have created a 400x600 canvas area. The chartName parameter is used for the id of the canvas element.
c. For now we have an empty SetupScript method. This method will eventually build the JavaScript required to render the bar graph.
d. The <noscript> tag holds the message to display when JavaScript is not enabled on the browser.
e. Point to note is the HtmlString object that is returned. The HtmlString is a special object that indicates to the Razor view engine that it should not Html Encode this string any further. If we use string instead of HtmlString, the Razor engine automatically Html Encodes the string and we see the markup as text instead of rendered Html.

Step 6: The SetupScript method: The setup script method has the JavaScript that actually renders the chart on the canvas. The original code is borrowed (with permission) from this project. A demo for it is available here. We have to make the following changes so that it accepts any data source instead of the fixed data source assigned to it in the demo. We have also updated the code to use the strings passed in for x-axis and y-axis labels. Beyond this the animation and rendering code is pretty much the same.

a. The variable initialization change

Earlier we had a hard-coded array of strings that was rendered on the canvas. Now we have the Json string that is created from the data source that was passed to the helper.
b. Changes to the barChart() method to set data source on the client side.

In the barChart method we earlier had no parameters and the elementId was hard-coded, now we use the value that’s passed into the helper.
We also pass a data parameter that is assigned to the data source of the graph.
c. Changes in drawMarkers() method to use the values passed into the helper for the x-axis and y-axis label

d. Changes to handle two-dimensional array of points instead of one-dimensional array of comma separated strings.


In the original code, the data source is an array of strings. Each element in the array has two comma separated values, represent the year (at index-0) and number of hits (at index-1). We have updated our data source to be a two-dimensional array and hence we don’t need to do a string split to get the value. We directly access the value using appropriate indexes. This change is at three places in the code. One of them is shown above.

With these changes in place our Chart, HtmlHelper is ready to be tested in an ASP.NET Web Application

Integrating the Custom Helper in a MVC Web Application

With our Helper all set, we add an MVC Web Application to our solution and call it DotNetCurry.HtmlHelpers.WebHarness. We use the Internet template that gives us a default Index.cshtml to put our Helper in. The following steps guide us through the integration effort

Step 1: Add Reference to the HtmlHelper project.

Step 2: Add a Model class in the Models folder.


This is our view model that will hold the data to be rendered in the Graph.

Step 3: Update the HomeController to create and pass sample data model.



As seen above, we create an instance of our ViewModel class and add some test data into it. We pass this data on to the Index view, where the HtmlHelper will use it.

Step 4: Update the Index.cshtml markup to use the helper


The changes in Index.cshtml highlighted above, from top to bottom are as follows

a. Declare the model to be used in the page.
b. Add using to include the custom HtmlHelper
c. Added the HtmlForm inside which we use our Chart Helper extension. We give it an id=’sampleChart’, pass it the Model.Data and provide the labels for the x and y axes.
d. Finally in the jQuery document ready function, we initialize the chart by calling the barChart() method.
e. Our final effort looks as follows.



To change the graph change the data set coming from the controller.

That brings us to the end of this tutorial. We round off with some of the improvements possible.

Possible Improvements

1. Update the script to be able to bind to any Json object.
2. Use jQuery plugin syntax so that more than one helper can be created per page.
3. Allow more flexibility like passing parameters for bar colors, size of chart etc.
4. Allow multiple data sources to show comparison side by side.
5. Add more chart types like Pie etc.

Conclusion

Though they sound esoteric HtmlHelper extensions is a rather simple mechanism to inject rich functionality in a componentized way in ASP.NET MVC applications. We converted an existing HTML5 chart, originally created using plain HTML5 and JavaScript into a Chart HtmlHelper with very little code. For large projects, HtmlHelpers are a neat way to encapsulate small pieces of re-usable UI functionality.

Introduction

MVC4 is really trying to break new ground in helping developers get to market more quickly and with a product that adheres to the emerging standards of today. A tough thing to ask of any technology, to be sure, but it's making some decent strides in the right direction.

Already the tutorials and blogs posts are popping up quicker than mushrooms on the midden heap. We highlight a few here that you definitely shouldn't miss which deal with key upcoming features...

ASP.NET MVC  4 Hosting

If you are looking for a QUALITY, AFFORDABLE host that supports ASP.NET MVC 4 Hosting, you can take a look at ASPHostCentral.com



ASP.NET MVC 4 Overview - Part 2

Jon Galloway goes into some significant detail here about some of the changes coming our way in the new version. He talks about the new default templates that come out of the box and the reasoning behind them.

He also talks about the new adaptive rendering taking advantage of CSS media queries and the usage of the viewport meta tag to help improve the mobile user experience. Overall a solid post that will stand the test of time. Check it out...

ASP.NET MVC 4 Bundling and Minification

Bundling and Minification of assets have to be two of the most tedious things to setup on a new web project. In this excellent post, David Hayden goes through exactly what you need to do to make the process as seamless as possible in MVC4.

Don't make the mistake of leaving this to the end of the project. You'll have deployment nightmares you didn't dream of and you'll be kicking yourself for not smoothing out the wrinkles. Do it early, and you'll thank yourself everyday for that small mercy...


Micro ORM Data Mapping with PetaPoco and ASP.NET MVC 4

Getting tired of working with the verbosity of Entity Framework classes and mapping? Well, you're not the only one, and in this quality post, Greg Arroyo takes us for a lap around the track using PetaPoco as your Micro ORM in MVC4.

Micro ORMs really are here to stay, and in some ways, more broadly applicable to web applications of today where everyone is trying to keep things more simple. If you haven't tried one yet, take this opportunity to get clued up on these fantastic tools.


ASP.NET MVC 4 Web API Routes and ApiController

Once again David Hayden masterfully takes us through a key piece of architecture that is going to be very important to anyone who will be working with MVC4. He details what seems to be a very slick piece of integration work between the new Web API framework and MVC4, and he throws in some OData queries for good measure.

It's short and sweet, and just enough to get you going, and whet your appetite for how to architect your solutions around your own APIs, allowing for more decoupled designs with less possible points of failure.


Getting started on your first Single Page Application

As with the introduction of any new method now encompassed in a technology, it's best to start with what comes straight from the horse's mouth. This Walkthrough put together by Brad Severtson gives you a great introduction, and leaves the mind boggling as to the possibilities.

If you've ever wanted to build your own Gmail and specifically wanted to do it with MVC, then go ahead, knock yourself out! (no pun intended)..

ASP.NET MVC 4 was released in beta by the Microsoft ASP.NET MVC Developer Team and it comes with a number of really cool features: Bundling and Minification Support of CSS and JavaScript, Database Migrations using Entity Framework 4.3, Web APIs, Mobile Web with support for jQuery Mobile, Real Time Communication via SignalR, and Asynchronous Support. The Database Migrations using Entity Framework Code-First is really cool and is very much like Rails where you can change your code and then via Package Manager add migrations and update your database as your code evolves. Because the EF Migration Files and Configuration get added to your Visual Studio Solution, all the database migration changes get added to source code.

If you are looking for a quality ASP.NET MVC 4 Hosting provider, please have a look at ASPHostCentral.com


   

ASP.NET MVC 4 and Entity Framework Code-First

ASP.NET MVC support for EF Code-First has been there since ASP.NET MVC 3. To jump start playing with Database Migrations start an empty ASP.NET MVC 4 Project and use Package Manager to install or update Entity Framework to the latest version that includes Database Migrations.

Install-Package EntityFramework

Add a simple Product Class that represents a product in your E-Commerce Website. Let's intially make Product simple by just providing an Id and Title to it.

public class Product {
    public int Id { get; set; }
    publis string Title { get; set; }
}

Run the Add Controller Recipe in ASP.NET MVC 4 to add a Products Controller that uses Entity Framework to read/write to the Database of your E-Commerce Website.



Once the Add Controller Recipe is finished you will have a working ASP.NET MVC 4 Website that reads and writes products to the Database using Entity Framework. The ProductsController was created along with all actions and views that display, create, update, and delete products.

Enabled Database Migrations to ASP.NET MVC 4

Now we want to enable database migrations to ASP.NET MVC 4 by using the Package Manager Console.

Enable-Migrations

Enabling database migrations creates a new Migrations Folder in your Visual Studio Solution as well as an InitialCreate Target Migration that has both an Up and Down Migration. The Up Migration creates the Products Table while the Down Migration drops the Products Table.

public partial class InitialCreate : DbMigration {
    public override void Up() {
        CreateTable(
            "Products",
                 c => new
                 {
                      Id = c.Int(nullable: false, identity: true),
                      Title = c.String(),
                  })
                  .PrimaryKey(t => t.Id);
         );
     }

     public override void Down() {
          DropTable("Products");
     }
 }

Add New Database Migration to ASP.NET MVC 4 Website

Now let's say we want to add more properties to the Product Class as well as make Title a Required Property and a length of 255 characters.

public class Product {
    public int Id { get; set; }

    [Required,MaxLength(255)]
    public string Title { get; set; }

    public string Description { get; set; }

    public decimal Price { get; set; }
}

One can now add a data migration as well as update the database via the Package Manager Console.

Add-Migration AddDescriptionPriceToProduct
Update-Database

The Add-Migration command creates another file in the Migrations Folder of our ASP.NET MVC 4 Project and the Update-Database command updates the database with the new Description and Price Columns as well as modifies the Title Column to be only 255 characters and not nullable.



If you look at the ASP.NET MVC 4 Database before and after issuing this Database Migration you will notice the effect.



And, of course, the new Database Migration File has the approprite Up and Down Methods.

public partial class AddDescriptionPriceToProduct : DbMigration {
    public override void Up() {
        AddColumn("Products", "Description", c => c.String());
        AddColumn("Products", "Price",
            c => c.Decimal(nullable: false, precision: 18, scale: 2));
        AlterColumn("Products", "Title",
            c => c.String(nullable: false, maxLength: 255));
    }

    public override void Down() {
        AlterColumn("Products", "Title", c => c.String());
        DropColumn("Products", "Price");
        DropColumn("Products", "Description");
    }
}

Conclusions

If you are a Rails Developer moving to ASP.NET MVC 4, you will find the Database Migrations support in Entity Framework a nice addition to the tooling. And, of course, those ASP.NET MVC 4 Developers that love Code-First Development with Entity Framework will love the new Database Migrations support in EF 4.3. Don't forget to check out other ASP.NET MVC 4 Features such as bundling and minification of CSS and JavaScript, Web API's, Asynchronous Support, and the mobile web templates. ASP.NET MVC 4 is still in beta at this point, but it has a go-live license.

First of all I want to make clear that most features aren't MVC-specific features. However, MVC does implement most of them out-of-the-box, while Web Forms needs some more installation and configuration work.

Front-end

Minification

There are some really neat features on the front-end part of MVC 4, first of all there's minification. Minification means that all spaces, enters and comments are removed from your CSS / Javascript files (including coffee, SASS and LESS), and that variable names are replaced with shorter variable names (such as a, b, c, etc.). This means that less data needs to be transferred to the visitors of your website, resulting in a faster page loading time, etc. Probably a feature that any front-end developer will love.

Bundling

Another cool feature that is often mentioned in one sentence with minification is bundling. Bundling means that you can have separate CSS files (e.g. one for your content, one reset style sheet, one for your layout) that are 'bundled' into one CSS file. ASP.NET does this by convention (but it's also configurable), for example: the reset.css will be placed in the bundle first, etc. This means that you only have one request instead of multiple requests, again resulting in a faster page load time.

Mobile web

Much has been done to improve the way MVC 4 behaves on mobile devices. There's now a mobile application project type that creates a nice lay-out that uses JQuery mobile to do all kinds of fancy stuff. MVC 4 also tries to render your lay-out in a mobile compatible way. This means that your elements are properly resized to fit inside the screen of mobile devices. But this is not the only feature, nor is it the most exiting feature. The most important mobile web feature (in my opinion) is the fact that you can now create device specific views. This allows you to create specific views for Windows Phone 7 devices, for Android devices, etc.

Project templates

For those who just want to make a quick prototype there are new project templates that look pretty fancy compared to the old project templates. Below is an overview of the new templates, the left template is the default template when you choose the 'internet application' project type, the second is the 'single page application' type and the third, obviously, the mobile type. The new project types also support AJAX login and OAuth.

Back-end

Web APIs

A very exiting new feature of ASP.NET is the introduction of Web APIs. This is another name for the new controller type, namely the ApiController. The ApiController makes creating an API much easier compared to WCF. Just like the default MVC controllers you can mark methods to be HttpPost methods, HttpGet methods, etc., but there are many new features to this.

The ApiController now allows users to perform queries against the API with OData if the ApiController method returns IQueryable<T>, it's possible to return specific HTTP codes to the consumer of the API, there's improved testability and IoC support, and more features that you will love.

Since the ASP.NET team and the WCF team have been merged, the new ASP.NET Web API wil replace some parts of WCF. This is a good things because the Web API is really easy (and flexible) to work with.

If you want to know more about ASP.NET's Web API I recommend Scott Guthrie's blog post about it.

Async

There was Async support in MVC 3. This meant that you need to have two methods: an Async method and a Completed method. MVC 4 removes the need for two methods and simplifies the way tasks are defined. Below are two examples:

The MVC 3 approach:

public void IndexAsync(string city) {
    AsyncManager.OutstandingOperations.Increment(2);
    NewsService newsService = new NewsService();
    newsService.GetHeadlinesCompleted += (sender, e) =>
    {
        AsyncManager.Parameters["headlines"] = e.Value;
        AsyncManager.OutstandingOperations.Decrement();
    };
    newsService.GetHeadlinesAsync();
     SportsService sportsService = new SportsService();
    sportsService.GetScoresCompleted += (sender, e) =>
    {
        AsyncManager.Parameters["scores"] = e.Value;
        AsyncManager.OutstandingOperations.Decrement();
    };
    sportsService.GetScoresAsync();
}

public ActionResult IndexCompleted(string[] headlines, string[] scores, string[] forecast) {
    return View("Common", new PortalViewModel  {
        NewsHeadlines = headlines,
        SportsScores = scores,
    });
}

The MVC 4 approach:

public async Task<ActionResult> Index(string city) {
    var newsService = new NewsService();
    var sportsService = new SportsService();    

    return View("Common",
        new PortalViewModel {
        NewsHeadlines = await newsService.GetHeadlinesAsync(),
        SportsScores = await sportsService.GetScoresAsync()
    });
}

As you can see the MVC 4 approach is much shorter and much easier, probably leading to more people using asynchronous methods. The code is still compiled into the same intermediate language, it's just syntactic sugar.

Real-time communication

There's also support for WebSockets and a new open source framework called SignalR that allows you to set up a real-time multi-user interactive website in a real easy manner. I highly recommend reading Scott Hanselman's blog post about SignalR and the official SignalR Github project.

Database migrations

The last feature that I wanted to mention is probably the coolest new feature. However, it's rather an Entity Framework feature than an ASP.NET feature. I'm talking about Entity Framework 4.3's new Database Migrations.

What it means is that Entity Framework can generate classes with Execute/Unexecute (actually they are called Up and Down, but I don't think those names really describe what they do), performing any database modifications that you've made. For example: let's say we have an entity called Person. If I wanted to add a property called 'Age' to Person entity, Entity Framework would generate a class for me with two methods: the Up method that adds the Age property to the Person table in the database (or whatever we've mapped the Person entity to) and the Down method that removes the Age property from the Person table. This allows us to rollback any changes, or easily perform updates on the database.

Entity Framework also allows us to generate SQL so we don't have to write change scripts manually any more. Automating the generation of change scripts can significantly reduce the time it takes to deploy your application, allowing the developers to focus on developing new features.

ASPHostCentral.com, the leader in ASP.NET and Windows Hosting Provider, proudly announces that we have supported the latest ASP.NET MVC 4.0 BETA Hosting.   

To support Microsoft ASP.NET MVC 4.0 BETA Framework, we gladly inform you that we provide this beta account FREE of charge for a limited time (* terms and conditions apply). 



New Features in ASP.NET MVC 4

This section describes features that have been introduced in the ASP.NET MVC 4: 
- Enhancements to Default Project Templates
- Better Support for Mobile Project Template
- Enhancement in Display Modes
- Mobile Project Template support for VB.NET
- Dependency Injection Improvements    

Terms and Conditions in Using this ASP.NET MVC 4.0 BETA Account 

The followings are the features you will get under this FREE ASP.NET MVC 4.0 BETA Account: 
- ASP.NET MVC 4.0 Beta Framework
- 1 Website/Domain
- 100 MB disk space
- 100 MB bandwidth
- 50 MB SQL 2008 space
- 24/7 FTP access
- Windows Server 2008 Platform

If you want to participate in this BETA program, there are several rules you need to understand: 

- As this is a beta version, not all the features are available. They may be some issues on this beta framework, which will be fixed upon the full release of ASP.NET MVC 4.0 Framework

- ASPHostCentral.com does not guarantee the uptime of the sandbox solution. Additionally, we do not keep/store any backup of your files/accounts

- ASPHostCentral.com does not guarantee rapid response to any inquiries raised by a user

- This free account is only meant for testing. Users should not use it to store a production, personal, e-commerce or any blog-related site

- This free account is used to host any ASP.NET MVC 4.0 beta website only. Any questions that are not related to ASP.NET MVC 4.0 BETA will not be responded. A user shall not host any non-ASP.NET MVC 4.0 site on this free account either

- ASPHostCentral.com reserves full rights to terminate this beta program at any time. We will provide a notification on our Help Desk System prior to the termination of this program

- ASPHostCentral.com reserves full rights to terminate a user account, in which we suspect that there is an abuse to our system

- Once this beta program is terminated, your account will be completely wiped/remove from our system.

- This offer expires on 31st May 2012

If you wish to participate in this FREE ASP.NET MVC 4.0 BETA Program, you must register via https://secure.asphostcentral.com/BetaOrder.aspx

One good news is that MVC 4 is also available via NuGet. To install MVC 4 via NuGet, type following in the Package Manager Console.

For more detail regarding NuGet package please visit http://www.nuget.org/List/Packages/AspNetMvc

ASP.NET MVC 4 for Visual Studio 2010

If you are using Visual Studio 2010 then you can use MVC 4 with Visual Studio 2010. To install MVC 4 via Web Platform Installer for Visual Studio 2010 please visit following link: http://www.microsoft.com/web/gallery/install.aspx?appid=MVC4VS2010&prerelease=true

ASP.NET MVC 4 for Visual Studio 11 Developer Preview

If you are using Visual Studio 11 Developer Preview then you can install MVC 4 in Visual Studio 11 Developer Preview via following link: http://www.microsoft.com/web/gallery/install.aspx?appid=MVC4VS11&prerelease=true

ASP.NET MVC 4 Direct Download Link

For Visual Studio 2010, first you need to install Visual Studio 2010 SP1 KB983509 via http://download.microsoft.com/download/2/3/0/230C4F4A-2D3C-4D3B-B991-2A9133904E35/VS10sp1-KB983509.exe

MVC 4 Direct link for Visual Studio 2010

http://download.microsoft.com/download/E/D/7/ED7CB028-2CBD-4E26-87D5-C9164A0B4849/AspNetMVC4VisualStudio2010Setup.exe

MVC 4 Direct link for Visual Studio 11 Developer Preview
http://download.microsoft.com/download/E/D/7/ED7CB028-2CBD-4E26-87D5-C9164A0B4849/AspNetMVC4VisualStudio11Setup.exe

Useful Links

- http://asp.net/mvc/mvc4 for latest update regarding MVC 4
- http://forums.asp.net/1146.aspx ASP.NET MVC forum

With release of ASP.NET MVC 4 Developer Preview, ASP.NET MVC team introduces a new default project template for MVC 4. New template has following improvements.

Cosmetic Improvements

New MVC 4 project template has cosmetic improvements prior to MVC 3 project template. And it will help community to create good looking modern websites with the default template itself without investing more in template designing.



Adaptive Rendering

Along with cosmetic improvements, new MVC 4 template used technique called Adaptive Rendering which will help in proper rendering in desktop browser as well mobile browser also without making any changes. To see Adaptive Rendering in action, resize browser window to be smaller and accordingly MVC 4 template layout will be changed to fit with screen size.


Rich UI

Another major improvement with MVC 4 default project template is use of JavaScript and jQuery plugins to provide rich UI. Click on Register and Login link to see rich UI in action.

With ASP.NET MVC 4, it’s even easier to setup and carry out a project which target mobile and tablet device. Yes MVC team introduce a new project template with MVC 4 which target mobile and tablet platform. This project template is build on the base of jQuery Mobile. And hence it is also optimized for better experience for touch screen

To get started with Mobile Project Template in MVC 4
Create a new ASP.NET MVC 4 Web Application
Select Mobile Application template when it ask to select project template

As far as the server side code (Controller, Model) is concern, it is same structured as Internet Application template. But responsibility of well rendering and well behavior for touch media is left on jQuery Mobile.

Inspecting Script folder of Internet Application Template and Mobile Project Template, you will find additional jquery.mobile-1.0b2.js file which is core script of jQuery Mobile included in Mobile Project Template of MVC 4.

Another major difference between Internet Application Template and Mobile Project Template is in its view. Inspecting _Layout.cshtml, you will notice some additional script reference and script in Mobile Project which is used by mobile or template device. In addition to script, another major difference in MVC 4 Mobile Project Template View is use of data-role and other attribute which is required for Mobile page structure and it used by mobile device and jQuery Mobile for proper rendering and behavior in touch screen and Smartphone