We've probably all heard of Microsoft's "Flex killer", SilverLight, but how does it stack up against Flex? As a simple comparison exercise I thought I'd try and reproduce the Flex contacts database in SilverLight.

By the time I'd added one XML-consuming DataGrid I gave up in frustration. I don't think Flex has much to worry about for the time being.

Here's the Silverlight app I started which is consuming the same XML as it's Flex counterpart. As you can see, I didn't get far.

Getting Started

To start developing the SiverLight (SL) app I launched Visual Studio Web Express (free!) and created a new SL project.

For the sake of argument let's assume most Flex or SilverLight business applications are going to be centred around some kind of Data Grid / "view", which fetches XML from a web server. Because most apps are like this. Are they not!

So, first thing I did was add a DataGrid and then I did a quick Google to find how to make it consume XML from a URL. I quickly found the code I needed and pasted/modified it to work with my own XML schema.

The C# code-behind for the SL app is, in essence, like this:

namespace SilverlightDominoDemoApp
{
    public class Contact
    {
        public string ID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string DOB { get; set; }
        public string Email { get; set; }
    }

    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();

            //make a new WebClient object
            WebClient client = new WebClient();
            client.DownloadStringCompleted += client_DownloadCompleted;
            client.DownloadStringAsync(new Uri("http://www.codestore.net/apps/contacts.nsf/vwContactsAsXML?OpenView"));
        }

        void client_DownloadCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
            if (e.Error == null)
            {
                XDocument xml = XDocument.Parse(e.Result);

                var contacts = from contact in xml.Descendants("documents").Descendants("document") 
                    select new Contact
                    {
                        ID = contact.Attribute("id").Value,
                        FirstName = Convert.ToString(contact.Element("first_name").Value),
                        LastName = Convert.ToString(contact.Element("last_name").Value),
                        DOB = Convert.ToString(contact.Element("date_of_birth").Value),
                        Email = Convert.ToString(contact.Element("email").Value)
                   };

               myDataGrid.ItemsSource = contacts;
            }
        }
    }
}

What this code does is fetch the XML and then, in the "on complete" event listener for the web request it loops all the "document" nodes using LINQ and creates a new object based on the Contact class. It then binds them to the data grid.

At this point alarm bells were ringing. What's this strongly-typed class I need to add? This means that to add or remove columns I need to modify the class and re-compile it all?!

You might remember in part 1 of my Flex App Basics series I talked about building views remotely. The idea being that the grid is designed on the server. The XML defines the columns to display as well as the data for the grid. The SilverLight way looks like it won't adapt itself to working this way. At least not easily. I'm sure there's probably a way to do it, but if it requires an in-depth knowledge of SilverLight in the first place, then it's failed at the first hurdle.

One of the things I have always loved about Flex is how easy it is pick up and how intuitive it is to develop with. Lots of what I've found out about Flex I've found out simply by guessing what might work, trying it and finding out it does.

On the other hand, after spending a couple of hours with SL I've found it to be quite un-intuitive. Almost as though it subscribes to the "it's enterprise class, so it needs to be complicated". You can tell it's a Microsoft product.

As an example, I could find no easy way to set the width of the DataGrid to 100% as percentage values aren't allowed. While I'm sure there's a way to do this, the fact I even need to think about in the first place is kind of off-putting.

On the plus side. The Silverlight app was created at no cost (thanks to the Express version of Visual Studio I used), whereas Flex/Flash Builder Pro cost me about 400 quid! Although I see that as no price considering what I've had out of it.

Summary

While what I did was far from an exhaustive comparison I did see enough to know that I don't think it's worth considering SL as a viable alternative to Flex.

Part of the reason I ever considered its use was that I assumed it would be easier/quicker to integrate it with an ASP.NET/Microsoft background. Whether this is true or not I don't know. Either way I can't imagine there's anything that radical about it that would make it worth re-learning what I know of Flex.

It just re-affirms my belief that Flex is an amazing product without limits as to what can be done with it.