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Thoughts on Software by Andrew Davey

Tuesday, February 19, 2008

VB.NET 9 as an HTML View Engine

VB.NET 9 introduces a clean syntax for expressing XML data. XHTML is XML so why not use VB.NET to generate it, instead of ASPX pages? People are creating view engines for the new ASP.NET MVC framework. How about a view engine that uses VB.NET XML literals?

The benefits to this approach include full intellisense and access to a the full VB.NET language when creating HTML.

I see a view as a function from some data to an XML element (the <html> element):

Function CustomersPage(ByVal title As String, ByVal customers As IEnumerable(Of Customer)) As XElement
    Return _
        <html>
            <head>
                <title><%= title %></title>
            </head>
            <body>
            <%= From customer In customers Select _
                <div id=<%= customer.LastName %>>
                    <h1><%= customer.FirstName %></h1>
                </div> %>
            </body>
        </html>
End Function

The important change from ASPX is that this is HTML in Code, rather than Code in HTML. As a result less "automagical" behaviour is required; It's just a function! This means AJAX features like "partial rendering", where a section of page needs to be updated, can be expressed by just calling a function that returns a <div> element. That same function can be used by the full HTML page function too.

ASPX "usercontrols" become simply functions as well. ASPX Master Pages are functions that have arguments for "placeholders" that get inserted into an template HTML page. Instead of having to reinvent a bunch of programming language concepts inside ASPX, we can just use a programming language that now support XML!

The only down side to this approach is we lose the IDE visual designer support. However, I find viewing an ASPX page that contains even simple conditional data rendering next to useless. I'd rather keep IE open and just refresh the page to see changes.

I am yet to embrace the MVC framework. I am waiting to see if the next release can better support Snooze framework ideas. However, there's no reason I can't use this VB XML magic in Snooze as it current is.

Tuesday, February 19, 2008 12:12:17 PM (GMT Standard Time, UTC+00:00)

Friday, November 02, 2007

Separating design and code with HTML and JavaScript

There is a lot of hype around Silverlight and WPF enabling true separation of developer and designer. This is certainly a great way to work. However, I don't think this is enabled only now by XAML. There is no reason the same cannot be achieved with HTML.

It seems like developers went so far down the server-side HTML generation route we left designers floundering with only CSS left in their toolkit. Whilst you can do some amazing things with CSS, sometimes you just need to change the HTML. If the HTML is riddled with <% %>, server controls or other template commands how is out poor designer going to work with the file?

My current attention is around using pure HTML and putting all dynamic content generation into JavaScript. The only thing to enforce on the HTML is that certain elements have known "id" attribute values.

Friday, November 02, 2007 4:42:04 PM (GMT Standard Time, UTC+00:00)

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