HTML Helpers are nothing but the way of rendering HTML on the view page in ASP.NET MVC. Typically what we have in traditional ASP.NET web forms is Web Controls to achieve same functionality but with the evolution of MVC pattern , you don't have any web controls to add on to the view pages.

In simple words - it is just a method which returns you a string , and string is HTML.

Example of HTML Helpers:

ASP.NET MVC framework ships with various inbuilt HTML helpers such as ActionLink , Label.
Lets take a look at how a HTML helper is added to the view page. I am considering Razor view engine for this example.

@Html.ActionLink("Display Name of Link", "MethodName", "ControllerName");

Example above shows how OOB Action Link is used to render the HTML hyperlink on the view page.

Another example is shown as below where it is used to render the Html label tag to render Store Name property of model class. 

@Html.LabelFor(model => model.StoreName)

Why to use Html Helpers?

Question might have poped up in your mind by now that Html helpers are just going to render the string of html then why do I need to use them ? If I know the Html syntax then why not add the Html directly on to the view page? 

Answer is simple, it depends how clean and consistent you want to make your application. of course you can do the direct addition of html tags on your view pages but if you observe second example - you can see that it is simply rendering the label tag on view page for a property in model at run time. so it just for making developer's life more easy and to have the cleaner html for your view page.

Need of Custom Html Helpers?

Well, there is always need to do some custom stuff on top of what framework offers, and reason for doing this is either business requirement or to get things done in smarter way.

Writing a custom Html helper is nothing but writing an extension method. you are actually writing an extension method for HtmlHelper class.

Being a SharePoint developer I always find this task similar to creation of a web control where you override the render method of base class and do the custom Html rendering. 

Creating Custom Html Helper

All right , for demo purpose I will keep the example simple - I will simply write an Html helper which will render the header of any content on view page.

This is done simply by using the <header> tag of Html 5.

Step 1: Define your custom static class for creation of your custom Html helpers

public static class DemoCustomHtmlHelpers
{

}

Step 2: Add static method to the class and make sure that return type is MvcHtmlString. Write an input paramter of method as HtmlHelper and also a string for which the header tag needs to be generated.

You might need to add System.Web.Mvc namespace to your class.

public static MvcHtmlString Header(this HtmlHelper helper, string content)
{         


}

Step 3 : Add the rendering logic in the method , you can take help from TagBuilder class to generate Html tags to be rendered.

public static MvcHtmlString Header(this HtmlHelper helper, string content)
{
   var tagBuilder = new TagBuilder("header");
   tagBuilder.InnerHtml = content;
   return new MvcHtmlString(tagBuilder.ToString());
}

Step 4: Build the project and open any of the view page. Now you can use your custom Html helper to render the header. Make sure that your view page has correct using namespace for using your custom Html helper extension.

@Html.Header("Create")

When you observe the view page's Html , you will be finding the generated Html tag by our Custom Html helper extension

<header>Create</header>

Now, you can also try it and have fun with your own scenario.

ASP.NET MVC is everywhere, and if you judge from the the job adverts ASP.NET Web Forms is rapidly being consigned to the “legacy” category. So where does that leave developers like me, currently using Sitecore?
Although it seems to me that Sitecore is Web Forms to it’s back teeth, there are nevertheless some signs that it too is going MVC.

From Sitecore version 6.6 there is support for MVC straight out of the tin (or the installer, at least). This is great but how do you get from that install to not just an MVC project, but MVC 4 (.NET 4.5) using Visual Studio 2012?
The steps are available around and about, but this post seeks to update the process to the latest version of Sitecore and pull it all together.

If you are really new to Sitecore MVC, probably the best place to start is here.

1. Create a Visual Studio Project from the install

a.) Using the latest version of Sitecore (Sitecore 6.6.0 rev. 130214), create a new instance
b.) Create a new Empty Website with Visual Studio 2012 using .NET 4 (but NOT MVC)
c.) Copy the Sitecore instance into your Empty Project Directory, and include the files (and Assembly References) into it. I found that the best way to get the Assemblies in was to copy them to a third directory (not the bin directory), then browse to that and Visual Studio will add them, nice and cleanly.
d.) Take the global.asax from the Sitecore Instance, pull out the inline code and paste it into a new global.asax.cs
e.) Publish the Site

2. Make the project MVC3

a.) Unload the project, then right-mouse click to edit the project file. In the project file you will find an element

<ProjectTypeGuids>

add this GUID to it at the front of the list, separated by a semi-colon:
{E53F8FEA-EAE0-44A6-8774-FFD645390401};

b.) Reload the project you now have an MVC3 Sitecore project.

c.) You should now confirm that MVC3 is working:

(this taken from John West’s blog)

Create a the subdirectory /Views containing a nested subdirectory named Sitecore.
Create the /Views/Sitecore/index.cshtml file containing some Razor code (note that the @inherits directive is not necessary if the /Views subdirectory contains the proper web.config file, such as that installed when you create an MVC project in Visual Studio):

@inherits System.Web.Mvc.WebViewPage
@{
  Layout = null;
}
<html>
  <body>
  <h4>Index.cshtml</h4>
  <div>Model:
@{
  if (Model == null)
  {
<text>null</text>
  }
  else
  {
@Model.GetType();
  }
}
    </div>
  </body>
</html>

In the Sitecore Content Editor user interface, navigate to the /sitecore/layout/Layouts/Sample Layout item that defines the default layout.
Click the Content Tab.

In the Path field, enter /Views/Sitecore/index.cshtml, and save.

Either publish the layout definition item and view the home page of the published site (http://playground – not http://playground/default.aspx), or use the Page Editor. You should see content such as the following:

Index.cshtml

Model: Sitecore.Mvc.Presentation.RenderingModel

3. Make the Project MVC 4

a.) In the project Website Properties change the Target Framework to .NET 4.5

b.) Update the references from MVC3 to MVC4

all references in .config files need to reflect these versions:
System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35″
System.Web.WebPages, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35
System.Web.Helpers, Version=2.0.0.0, Culture=neutral, publicKeyToken=”31bf3856ad364e35″
System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35

these appSettings need to be added to the web.config:

<appSettings>
  <add key="webpages:Version" value="2.0.0.0" />
  <add key="PreserveLoginUrl" value="true" />
</appSettings>

further details here:

c.) In Solution Explorer, right-click on the References and select Manage NuGet Packages. In the left pane, select Online\NuGet official package source, then update the following:

ASP.NET MVC 4
(Optional) jQuery, jQuery Validation and jQuery UI
(Optional) Entity Framework
(Optonal) Modernizr

d.) Update ProjectTypeGuids element and replace {E53F8FEA-EAE0-44A6-8774-FFD645390401} with {E3E379DF-F4C6-4180-9B81-6769533ABE47}.

e.) If the project references any third-party libraries that are compiled using previous versions of ASP.NET MVC, open the root Web.config file and add the following three bindingRedirect elements under the configuration section:

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers"
             publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0" newVersion="2.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc"
             publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="4.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages"
             publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0" newVersion="2.0.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

f.) Finally, there is an incompatability with the Sitecore login page under .NET 4.5, to do with the use of an iframe. The file sitecore/login/default.aspx contains an iframe to the SDN that .NET 4.5 doesn’t like. Replace it with a div:

<iframe id="SDN">
  <div id="StartPage" runat="server" allowtransparency="true"
 frameborder="0" scrolling="auto" marginheight="0" marginwidth="0"
 style="display: none"></div>
</iframe> 

<div id="SDN">
  <div id="StartPage" runat="server" allowtransparency="true"
 frameborder="0" scrolling="auto" marginheight="0" marginwidth="0"
 style="display: none"></div>
</div>

and you’re off to the races. More detail here.

I should point out, of course that .NET 4.5 is not supported as yet by Sitecore, but with this you can play with 4.5… until Sitecore 7 arrives.

Good luck.

MVC 4 introduces many new features. In today post, I will talk about MVC 4 and enhanced default templates.

When you create a new project, the default website looks quite different from previous versions.  Besides the improved aesthetics, the default website has improved functionality thanks to a technique called adaptive rendering.

Adaptive rendering is where the page is rendered specific to the browser without any customization.  This is an absolute must for most developers today; write once, run everywhere.  The adaptive rendering is made possible thanks to a new CSS type -> media queries

@media all and (min-width: 640px) { #media-queries-1 { background-color: #0f0; } }
@media screen and (max-width: 2000px) { #media-queries-2 { background-color: #0f0; } }

After you creating a new website, you’ll be able to see the improvements in the default layout.

To see the adaptive rendering in action, open the page using a mobile device.

Here’s how the page looks on an iPhone.

And here’s how the page look on an iPad.

The page renders differently depending on the size of the screen.  Making the page do that without media queries is tricky.  Using media queries makes it simple.

One final thing to note is the default template takes advantage of jQuery UI also.  The Login and Register links show you how to use this JavaScript library to  provide a richer UI.  You can read all about the other features that are available to you with jQuery UI here.

Testing with Emulators

The best way I found to test what the site will look like is with FireFox and User Agent Switcher add-on,
which changes the user agent that’s sent to the browser.  That can be downloaded
here.

Some of you will face this problem when using Bundling and Minification in ASP.NET MVC 4. This post cover about how to fix relative CSS Path in ASP.NET MVC 4.

Recently, I hit a known problem with deploying to IIS virtual directories. It’s not a problem for ASP.NET which understands virtual directories and so if you ask for “~” or “/” will return “yoursite/virtualfolder”. However, JavaScript is run under IIS, which doesn’t understand this idea so well. Do “/” in JS and you’ll get back “yoursite” NOT “yoursite/virtualfolder”.

So what’s the fix? Well, for JavaScript there are a couple of answers. So I check my javascript. Based on this answer, I came up with this:

1. Add a hidden field to a masterpage:

  @Html.Hidden("HiddenCurrentUrl",  Url.Content("~"))

2. As one of the first things you do, ensure this JS runs. All it does it take the value in the field and store it:

var baseUrl = "";
baseUrl = $("#HiddenCurrentUrl").val();

3. Use baseUrl wherever you need to call things in JavaScript:

Silverlight.createObject(
            baseUrl + "ClientBin/SilverlightBridge.xap",  // source
            ...
        );

Hmm… But you know, that is not the problem. The problem is with the CSS file

    .link-button.cancel {
        background-image: url('../Images/appbar.cancel.darkgrey.png');
    }

A similar problem occures where these URLs start with a slash(/) because IIS interprets that incorrectly. You can’t invoke ASP.NET, which does know the right root into a CSS file

After some messing around, I came to this compromise, which works well. It also exposes some of the hidden power of using Bundling:

1. For any images you reference in CSS, move them into a relative folder, such as /images near the CSS. I know, this may be an unacceptable compromise for you. But actually, it makes a lot of sense. The image is probably only used by the CSS so it makes sense to have it nearby, not in some global /images folder.  
2. In order to make this work, you need to get your CSS (which you’ve bundled up) into the same place relative to the images you’re reference, or at least, you need to cheat the browser into thinking this happening.
3. So, for instance:
   
     bundles.Add(new StyleBundle("~/Content/DataTableStyle").Include(
   
   comes out the other end as:
   

Don’t forget that all your “static” content, such as images won’t be affected by Bundling and can be referenced using the folder structure you expect, i.e. the one you’ve set up in Visual Studio.

So… when you create the Style Bundle you give it a name which reflects where you have it in your Visual Studio folder structure, then it will pop out the other end in the same place, relatively, to the image files which it’s references! And because the Bundling is happening via ASP.NET, the URL of the CSS file, and wherever it is referenced, works fine in virtual directories!