The Future of DNN Speaks Razor - #2 But What is Razor?

As you might have heard, you have to migrate to Razor sooner than later, and the earlier you start, the more you will be creating future-compatible material today. This is part 2 of the Series The Future of DNN Speaks Razor. In this post I'll explain what Razor is, why it's not MVC (even though Razor is popular there as well) and more.

A first example of some code

The following screenshot shows a simple Razor template creating a list of questions with hidden answers. It's a part of the FAQ App I created last week:

Now just so you understand it a bit better I've added some color coding showing some features of Razor:

1. Orange shows a .net using statement - you can integrate any kind of .net library
2. Yellow shows standard placeholders - inserting any kind of variable directly inline
3. Blue shows the same thing as yellow, but inserting it as raw HTML (the default insert will escape HTML)
4. Green shows a loop

So What in the Gillette is Razor?

1. Razor is a text-templating system based using .net placeholders and allows you to write .net code into the template.
2. The classic use case is writing code like:
   <h1>@Content.Title</h1>
   which would then be replaced at run time with
   <h1>The Future Speaks Razor</h1>
3. A Razor inline placeholder can be much more complex and contain .net code like:
   <span>@(4+2)</span>
   <span>@((1+1==2) ? "it's true" : "it's not true")</span>
4. And Razor can also contain code blocks, which can again contain HTML like this:
   @{
   var x = 1;
   var y = x + 2;
   if(y > x)
   {
      <h2>it's large!</h2>
   }
   }
5. It's not limited to HTML and can also be used for any kind of text output. We often use Razor to template our e-mails, because it allows us to write very custom, complex output code outside our main line of code, just to create this e-mail. It also allows us to easily use different highly complex, smart e-mail templates for various purposes.

A More Complex Example

The following screenshot shows a Razor-Template

I've marked the segments with colored bars on the side. The picture shows

• Blue: A @functions block containing functions and variables needed by the entire view
• Green: two different segments, each with a loop. All very simple and easy to read
• Orange: a bit of code bridging some data to client side JS - like handing over a module-ID. This was all so much more complex with Webforms.

So What is a Razor good for?

Razor is ideal to dynamically create text - based on data or anything else…resulting in HTML, XML, JavaScript or simply plain text.

And What is it not Good for?

Technically, you could do everything in Razor, just like you could also create lemonade using a hammer and lots of lemons. But it's not the ideal use case. Razor is not ideal for generating binary data, for developing a data- or business layer. It's also not ideal for processing user input. And even though you could retrieve data in Razor (very easy, thanks to .net) you would typically not do it because of SoC (Separation of Concerns). Instead, data access should be in a separate code area containing all business and data logic.

Razor is NOT the same thing as ASP.net MVC

No. Razor is a view/templating-engine to combine data with a text-template and return a text-string. MVC uses it by default as the "V"-layer im MVC, but you could use MVC without Razor, and you can use Razor without MVC. The standard example is ASP.net WebPages - which are basically just some Razor-pages. 

Does Razor work with ASP.net Forms

Yes, it works very well inside and within ASP.net Forms. But it's very different - when you start using Razor, you are usually reminded of the good-old classic ASP days, before the it became aspX, because it's just HTML with placeholders. What's "missing" is the event-attachment, code-behind, view-state, post-back and a few other things. These are features that software developers usually like, but web designers hate.

Does Razor work with DNN?

It works perfectly well with and within DNN! In a following post I'll write how to get started. For the impatient, try the DNN-Razor Host Module and watch this video  or try packaged code apps by installing 2sxc and some of the Razor Apps like the Razor Basic Tutorials, List-Tutorials or the SQL and Peta-Poco Tutorials.