Lately I haven’t been such an active video game player as I used to be some months ago, but now I’m feeling that during this year and the next one I’ll come to my roots

Microsoft XBox 360

From Microsoft, as a XBox 360 owner I was glad to hear that XBox Live will have integration with Facebook and Twitter, my two main social networks. For gold membership owners will get full access to Last.FM through their XBox 360 systems.

But the best of all, that really got me crazy was Project Natal. My friend Marco wrote a post on his blog about it and it has 2 MUST SEE videos.

Nintendo

The news about Nintendo DS weren’t that appealing to me, since I don’t own a Nintendo DS, but it’s obvious that Nintendo is targeting young women with several games meant to them. The focus in user generated content is a great initiative. It doesn’t apply only to Nintendo DS applications but also video games with user generated levels.

As a Wii owner I really must buy Wii Sports Resort with Wii Motion Plus that is coming to stores in July.

As a fan of one of the best games I’ve ever played (if not the best) I was glad to ear that a Super Mario Galaxy sequel is coming. You can watch the trailer at GameTrailers.com

Nintendo also announced Wii Vitality Sensor which can read your vital signs and find out whether you’re anxious or focused, etc. I’m not really convinced, but I’ll wait and see.

Sony Entertainment

 I own a PSP 3000, and I won’t buy PSP Go, but a new handheld video game console it’s always good news for gamers. And I didn’t pay attention to Playstation 2 and 3 news…

You can what the 3 press conferences though Gamespot at http://e3.gamespot.com/press-conference/

A few months ago I started using IE8 as my main browser in my personal laptop. And very happy about it because it’s lighter than Firefox, and I don’t really need all the extensions outside work. But I missed Userstyles…

After searching for a while I found information about custom cascade style sheets in IE in a Microsoft article.

By following this step-by-step tutorial, you can set a custom css file for your browser. The changes are applied after browser restart, and it’s somewhat limited when compared with userstyles, since you can’t turn on/off setting on the fly and the css rules are global, which means that you change a class properties for a website, and you happen to navigate to another one that uses the same class, the css rules will also be applied.

Nevertheless, now I was able to remove ads from Windows Live Hotmail in IE8, remove the search bar that I don’t use and so on.

Edit: I just “hate”, not “have”.

A segunda edição do evento da comunidade PocketPT.net para os Profissionais de tecnologias móveis e relacionadas, dá continuidade ao sucesso obtido pela primeira edição.
Este ano, de modo a oferecer um conjunto de conteúdos mais alargado, as duas tracks foram divididas em dois dias, sendo o primeiro dia reservado a programadores e o segundo a profissionais de TI.
Consegue-se assim uma maior riqueza e abrangência de conteúdos e intervenientes.

Mais um evento sobre Windows Mobile promovido pela comunidade PocketPT.NET. A julgar pelos a que já assisti irá valer bem a pena. Inscrições abertas. Mais informações no site oficial.

A feature that I wasn’t able to find was cleaning all the cached data. You can remove cache for a specific page using HttpResponse.RemoveOutputCacheItem(”pagename”) but to remove all pages (which can have several cached versions each) you have to use some kind of workaround. You can use a Cache dependency relying in a item stored in HttpContext.Cache items collection, but for my particular scenario it wasn’t the right solution. Why?

If you have several front-end servers serving your website, you have independent cache systems, so when forcing a cache cleaning, you will force it only for the front-end serving your request. To solve this issue I’ve created a cache system relying on a file dependency. This way, when I change that file, all the front-end servers will clean their cache. I’ve included a CacheManager class that has the usual Add method, that automatically add the file dependency to cached data ( usually using Response.Cache.Add) and not only output cache.

Download source code and have fun exploring it.

Since Linq to Objects has some similarities with SQL, I got the idea of trying the same approach that I used several times in SQL, which was ordering a SELECT statement using ORDER BY RAND().

The result is shown bellow.

It uses the Extension Methods syntax of Linq to save some bytes on the source code

The usage of your settings is shown bellow. The configuration section handler class is used in order to access the configuration properties.

I’ve shown you the usage of a class called SiteSettings, but how does it’s definition look? It is a class that inherits the ConfigurationSection class. The configuration section properties are defined by adding public properties that correspond to Configuration Elements. While adding these properties you can define the name of the XML node that you will use in the web.config file and either if the property is required or not. In the example bellow you can see the Singleton design pattern in order do avoid creating several instances of the class and loading the section from the configuration file each time I access the values.

In this example, we only have one configuration property. It is defined in the class bellow. It corresponds to a contact information. Each property of this class correspond to an XML attribute, and by using annotations you can define the name of the XML attribute, it’s default value, if it is required and even add validators such as regular expression validators. You can use several variable types such as strings, integers and event enumerables.

By using custom configuration settings this way instead of accessing ConfigurationManager.AppSettings as a dictionary of string values you get intellisense while using configuration settings, and best of all, automatic validation of the types, constraints and structure of the settings (checked when the settings are accessed for the first time).

The full demo project is available for download. I hope it gets useful to you.

]]> If you are an ASP.NET developer you must be familiar with web.config. Something that maybe you haven’t tried yet is to create custom configuration sections to store you application specific settings. Bellow you can see a web.config file that uses a custom configuration section. In the configuration/configSections element you must define which class is responsible for handling your configuration section. Then you can add your custom settings to the file as shown bellow.

The usage of your settings is shown bellow. The configuration section handler class is used in order to access the configuration properties.

I’ve shown you the usage of a class called SiteSettings, but how does it’s definition look? It is a class that inherits the ConfigurationSection class. The configuration section properties are defined by adding public properties that correspond to Configuration Elements. While adding these properties you can define the name of the XML node that you will use in the web.config file and either if the property is required or not. In the example bellow you can see the Singleton design pattern in order do avoid creating several instances of the class and loading the section from the configuration file each time I access the values.

In this example, we only have one configuration property. It is defined in the class bellow. It corresponds to a contact information. Each property of this class correspond to an XML attribute, and by using annotations you can define the name of the XML attribute, it’s default value, if it is required and even add validators such as regular expression validators. You can use several variable types such as strings, integers and event enumerables.

By using custom configuration settings this way instead of accessing ConfigurationManager.AppSettings as a dictionary of string values you get intellisense while using configuration settings, and best of all, automatic validation of the types, constraints and structure of the settings (checked when the settings are accessed for the first time).

The full demo project is available for download. I hope it gets useful to you.

]]> http://brunosilva.net/using-webconfig-for-custom-configuration-settings/525/feed/ http://brunosilva.net/linq-adding-element-to-collection-union-vs-concat/517/ http://brunosilva.net/linq-adding-element-to-collection-union-vs-concat/517/#comments Wed, 21 Jan 2009 11:45:50 +0000 Bruno Silva http://brunosilva.net/?p=517 Some time ago while developing a project I came across a problem related to Linq to Objects. I wanted do join a single object with a collection in order to transverse them with a foreach statement (the item was not allways present and I wanted to treat it as a regular element in the original collection).

Using the intellisense to find a Linq to Objects extension method that fitted my needs I didn’t find that particular functionality, but I thought about an alternative: creating a collection with the single element and joining the two collections with one of the two extension methods that seem promising to this new task: Union and Concat.

After reading the documentation and writing the example above I became aware of the difference. Union acts as a mathematical set operator, adding the elements of both lists into a single list without repeated elements. Contat, by the other hand keeps the repeated elements.

Foi lançado hoje um novo portal português destinado aos mais novos. É o Sapo Kids! Além de diversos conteúdos lúdicos e didácticos reunidos a partir dos diversos serviços do mundo Sapo, conta com parcerias como a Porto Editora ou até mesmo o MIT.

Realço a integração do Scratch no portal. O Scratch que nasceu no MIT permite aos mais novos criarem animações interactivas de forma simples e divertida enquanto aprendem. O Sapo Kids tem a plataforma Scratch totalmente em Português, tornando-a ainda mais atractiva às crianças portuguesas.

Antes mesmo do projecto criar raízes em Portugal já existia uma escola pioneira a utilizar o sistema do MIT. Espero que outras lhe sigam o exemplo agora com este portal Português.

Mais informações no site http://kids.sapo.pt

Portanto,

• 6 euros x 2 packs (2 pilhas cada) = 12 euros
• 14 euros * 1 pack * (4 pilhas) = 14 euro

O senso comum não nos diz que os packs de maior número de unidades deve sair mais barato? Ou pelo menos ter o mesmo preço? O meu diz que sim. Ou é um engano de marcação de preço, ou stocks distintos em que um deles ainda foi adquirido com preço antigo.

Mas a hipótese que me parece mais interessante é ser uma estratégia de marketing para ganharem uns trocos. Se toda a gente pensar como eu que os packs maiores saem mais barato ou igual, imaginem os vários 2 euros que ganham em cada pack (já nem falando na poupança na embalagem).

Tive sorte de geralmente ter a mania de comparar os preços, e depois deste episódio vou estar mesmo atento.

P.S.: Contei este episódio a uma pessoa que me disse que numa qualquer superfície o mesmo acontecia com os sacos de areia para gatos de 5 e 10 kg. Não comprovei

.NET Services

.NET Access Control Service

All communication with the Access Control Service relies on standard protocols such as WS-Trust and WS-Federation. This makes the service accessible from any kind of application on any platform.

Claims-based identity is on its way to becoming the standard approach for distributed environments.
By providing an STS (Securtity Token Service) in the cloud, complete with rules-based claims transformation, the Access Control Service makes this modern approach to identity more attractive.

.NET Service Bus

The Service Bus assigns your organization a URI root, below which you’re free to create any naming hierarchy you like.
This allows your endpoints to be assigned specific, discoverable URIs.
Your application must also open a connection with the Service Bus for each endpoint it exposes.
The Service Bus holds this connection open, which solves two problems.
First, NAT is no longer an issue, since traffic on the open connection with the Service Bus will always be routed to your application. Second, because the connection was initiated from inside the firewall, there’s no problem passing information back to the application—the firewall won’t block this traffic.

.NET Workflow Service

Running (workflows) in the cloud brings some limitations, however.(not all Windows Workflow Foundation activities are available: code activity isn’t).
WF-based applications running in the Workflow Service can only use WF’s sequential workflow model, for example.

Also, running arbitrary code isn’t allowed, and so neither the BAL’s Code activity nor custom activities can be used.

SQL Services

SQL Services is an umbrella name for what will be a group of cloud-based technologies.
(the first one available is SQL Data Services)
SQL Data Services doesn’t provide a standard relational database, nor does it support SQL queries.
LINQ C# syntax, with queries sent via either SOAP or a RESTful approach. The other is to use ADO.NET Data Services

Live Services

A mesh-enabled Web application must be implemented using a multi-platform technology, such as Microsoft Silverlight, DHTML, or Adobe Flash. These technologies are supported on all of the operating systems that can run the Live Framework.(targeting Windows Vista/XP, Macintosh OS X, and Windows Mobile 6).

After the yesterday’s announcement of Windows Azure, the brand new cloud-based Windows, today I started reading a little bit about it. This new platform seems promising, and I’ll write a bit about it in some of my next blog entries.

First of all I’ll talk about the Windows Azure, which is a part of the Azure Services Platform. It allows you to run applications and store data on the cloud (replace cloud by “a bunch o Microsoft data centers”). You can reduce the Total Cost of Ownership (I don’t say eliminate, because you will have to pay for the service), because you don’t have to build/buy/care about the infrastructure. You contract a service that is payed based on usage, so you can get scalable solutions even for start-up projects for which is difficult to predict the needs.

Computing

You can have 2 kind of applications running on Windows Azure. Web applications and workers (asp.net applications vs. something like the Windows services).

Web Role

Web applications are just like any web app that you write nowadays (receiving HTTP requests and responding) but in order to take advantage of the farm of virtual servers that Windows Azure provides you, your web applications should be stateless.

Well, not really stateless, but the state must be stored in a particular way. If you used session variables stored in the web server, you app would be attached to a particular server (the one to which the first request was made), this way any load balancing decision that lead your end-user to another server would lead to loss of that session data in the subsequent request… The right way to do it is to use cookies or (to prevent overhead on communications, or for security concerns) Windows Azure storage, which is available from all the virtual servers that serve your application.

Worker Role

Another option is to have an application that does some background work. They can’t have inbound communication, but can connect the outside world. They can read data from the Windows Azure Storage, and in the typical scenario, they get data from queues (which is one of the 3 storage mechanism of Azure). This kind of application can run indefinitely just like a Windows Service.

Storage

What about storage? There are 3 kind of storage that I’ll briefly refer.

Blobs - to store large amounts of unstructured data such as images, movies, binary data, etc. You can associate meta-data to blobs such as location and tags for a photograph or title of an audio file, etc. Whatever you need.

Tables - not regular relational tables, just a hierarchical set of entities and properties. You can access it’s data using LINQ and not SQL (to reinforce that this isn’t an SQL table :P)

Queues - As I wrote before the main purpose of queues is communication to and between applications instances with the worker role

All the storage is replicated 3 times in order to tolerate faults (at least some of them).

As far as I read, I wasn’t able to try it yet, the Windows Azure SDK allows you to develop your applications locally and getting some guaranties that when you deploy it into to the cloud it will work smoothly. Locally you can debug you application, which you won’t be able to in the cloud.

Next: .NET Services, SQL Services and Live Services

Last week I had a workshop about Microformats with André Luís sponsored by PrimeIT and Sapo. It was very interesting and really answered some of the questions I had about Microformats.

What are Microformats?

Designed for humans first and machines second, microformats are a set of simple, open data formats built upon existing and widely adopted standards.

Which Microformats did I implement in this blog after this workshop?

hAtom

hAtom is a microformat for identifying semantic information in weblog posts and practically any other place Atom (http://www.atomenabled.org/) may be used, such as news articles. hAtom content is easily added to most blogs by simple modifications to the blog’s template definitions.

Since, as André told us, the new feature of IE8 called Web Slices is based o hAtom, by adding the class
hslice next to the hentry class, now I also support Web Slices!

hCard

hCard is a simple, open, distributed format for representing people, companies, organizations, and places, using a 1:1 representation of vCard (RFC2426) properties and values in semantic HTML or XHTML.

xFolk

xFolk (from “xFolksomony”) is a simple and open format for publishing collections of bookmarks. It better enables services for improving user experience and sharing data in web-based bookmarking software.

I was glad to ear that support for Microformats is growing on the web, and the web browsers are becoming Microformats-aware. According to André, Firefox 3 (or 3.1, I don’t remember) already brings an API for Microformats, although there isn’t any support in the user interface. Maybe in FireFox 4 we’ll get it. And as I said before, IE is supporting one of the Microformats.

There are some web browser plugins that make Microformats usable. For FireFox you can get Operator which will add a toolbar like shown in the picture bellow. You can access the contacts, events, bookmarks, etc available in the current webpage.

For Internet Explorer you can get Oomph, but I wasn’t able to use it with my blog… Well, maybe in the future it will work better.

Adding Microformats support  in your blog or website can be pretty simple. It took me about 2 hours in this blog, thanks to a nice base Wordpress theme easily customizable.

In the last day of Shift’08 Conference I attended to a session about a project of investigation that I really liked. The speakers (authors of the project) weren’t good speakers and had difficulties to “sell the product”, but the project itself and their idea really pleased me. What is it?

TODAY is a piece of generative design for mobile phones.

It’s an application that visualizes personal mobile communication. It sits on the periphery of the machine, monitoring our connectivity through the number and type of calls we receive, subtly displaying them back to us, in the form of a generative graphic. Here, the visual result is a figurative and seemingly abstract picture – the story of your day. Some days will be really colorful and wired, others quieter and more reflective, either way the resulting visuals will always be personal, unrepeatable and unique.

They have a set of rules used in the creation of the elements of each drawing. Bellow you can have a taste of the main rules.

When I talked about this project to some people they were like “And what’s the use of it? Seems silly…” As far as I am concerned: NONE!!! But it is art! It is not meant to have an use. It is pretty and meaningful. Your day recorded in an image. Brilliant concept. That’s it. No “features”. This project gets funds from the Portuguese Ministry of Culture!

This software is free and it is available for download. The only drawback is that it targets only Symbian… When someone in the audience asked the authors about porting to other platforms they told that iPhone or Android would be great, but in the iPhone would be difficult to get information about your communications, so Android would be a nice option.

I was really sad that they didn’t even mentioned Windows Mobile, which I consider to be a great platform for development that is growing everyday. I haven’t ever tried something like this, but my feeling is that it wouldn’t be that difficult to get information regarding calls log and SMS’ log on a Windows Mobile powered phone.

Try this software if you can, really. Unfortunatly I won’t be able to… TODAY, Mobile Application.

Sometimes web pages have printing style sheets, other times copy-paste to Word is really effective. But if the web page is messy, this is a great tool.

It is worth giving it a try! Go to PrintWhatYouLike.com and start printing in a ecologic and cheaper way.

A área me usabilidade é-me bastante querida deste que tive a cadeira de Interfaces Pessoa-Máquina. Sempre que tenho oportunidade de aprendar mais sobre este assunto que tantas vezes é colocado de parte, tento aproveitar ao máximo.

Um destes casos é a User Experience Week que engloba uma apresentação pública e 2 workshops. Para os workshops não tenho budget mas na apresentação devo estar presente!

Parabéns à Fullsix e à Microsoft por mais uma excelente iniciativa conjunta.

Imagine for instance a concept called Color Classifier. We usually have several named colors such as red, green, blue, yellow, gray, orange, etc.  You have different flavors of each color, and you can consider different combinations of RGB colors the same color. How  can you, given a RGB Color code, name that color?

One approach is using Neural Networks (which is a unsupervised learning method) for classification.

I won’t talk about the details of Neural Networks algorithms, since it is the reason why many people avoid this kind of approach: complexity. I’ll just show you how, with a library that hides the implementation details, you can use them.

NeuronDotNet is a .NET library which allows you to use Neural Networks algorithms as a black box. They have some samples which can guide you, as they guided me.

The algorithm I’m using is called Self-organizing Map (SOM). The main idea is to generate a 2D map which topology (dispersion of the points and their positions) is based on the relation between the input data. Back to the example, from a set of random colors which can be represented as a vector with 3 dimensions (input), we generate a map with 2 dimensions, where similar colors get close to each other and completely different colors are set apart. The picture bellow represents the results.

(Left: input, Right: 2D map that results from the algorithm)

The number of colors that will be recognized (the number of neurons of the output layer) can be customized in the neural network configuration, prior to the training phase. In the example above I recognize 25 different colors.

Once the SOM algorithm runs in training mode, the resultant neural network is able to classify new colors into the different slots of the map. If you name each slot with the name of a color, you get a color classifier. In the example above you can label several flavors of green, blue, red,  brown, pink, etc. In each slot you have several stripes that represent the colors from the training set and in which slot they ended up.

In the demo application the basic steps are:

1. Play with the different settings (or leave them alone… take special attention to Layer Width/Height and Set Size)
2. Generate Training Set
3. Start (Learning)
4. Choose Color (to classify)
5. Classify (the neuron that best matches the selected color will be highlighted with a red border)

Download and try the Color Classifier. Keep in mind that a lot of the source code is UI-related, and not Algorithm-related, so don’t be afraid!

Download Demo | Download Source Code

When you enable Mail Goggles, it will check that you’re really sure you want to send that late night Friday email. And what better way to check than by making you solve a few simple math problems after you click send to verify you’re in the right state of mind?

As you can read above and by the challenges bellow it really looks like a test to find out if you are drunk or under the influence of drugs. lol

This Plugin is kind of useless, but you can find some more with nice features. Learn about Gmail Labs in the official Gmail blog.

O Sapo Code Bits aproxima-se! Este evento conta com concursos, workshops e bastante animação e troca de ideias. O ano passado não estive presente, mas estou a fazer os possíveis para ir este ano!

Para tal registem-se no site apresentando a vossa candidatura. Mais informações através do site codebits.sapo.pt e para notificações de última hora sigam http://twitter.com/codebits

Yesterday I tried a new version of a tool I didn’t know about. It is called GPS Cycle and it uses your built-in GPS receiver to track your position and draw a graph.

But the feature that I really like, is the ability to save your path into a file which can be read by applications such as Google Earth. This way you can review your tracking, if you go for a walk by foot or bicycle , or something like that.

If you enable the geo-referenced photographs in your phone, you can decorate your path with those pictures (with some additional work).

GPS Cycle is available at the XDA Developers Forum. You can enable the geo-referencing in your photos in HTC Diamond using  Diamond Tweak. (Other devices that have builtin GPS have similar tools that change some register keys).

Today I was amazed to realize that my University systems allow you to use the new Portuguese Citizen Card!

I’m pretty sure that almost no one will use this feature, but it is a nice initiative to embrace this new authentication mechanism.

A new Microsoft marketing wave has started with the motto “Windows Without Walls” as I read int Windows Vista Blog. Pretty nice concept and nice wallpaper.  But from a developer perspective the image is pretty funny. Take a look at the image bellow.

It seems that Windows is about getting some construction tools and hack our house around and using a hammer to get a hole where you need a hole.

Bom dia.

Acabei agora de realizar uma encomenda na loja online, e há algumas coisas que não percebo. Primeiro tive bastantes dificuldades em realizar a encomenda devido a questões de usabilidade: Ao seleccionar como local de entrega uma loja FNAC, as caixas de texto para expedição (morada, código postal, etc) ficaram inactivas (o que é espectável). No entanto permaneceram com preenchimento obrigatório, o que me obrigou a mudar o local de entrega para "Morada", preencher tudo, e só aí escolher a loja para entrega…
Quando é aberto o formulário para expedição, no envio para morada apenas aparece a opção de recepção das 9 às 18 horas, só preenchendo os diversos campos aparece a opção das 19 às 22h. Ora além da falta de
transparência para o utilizador, ainda se arriscam a perder encomendas por falta desta informação. Finalmente no pagamento, é-me pedido o NIB, o qual copio da minha aplicação de e-banking e colo na caixa de texto.
Recebo uma mensagem de "NIB incorrecto" à qual não é anexada qualquer informação do formato esperado, depois de tirar espaços, o código do país e os digitos finais de checkdigit, lá consegui submeter o pedido.
Têm sorte que não desisti a meio. Por fim em vez de uma mensagem de "Compra efectuada com sucesso, vá ao seu e-mail" tenho o carrinho vazio, levando-me a pensar que tinha perdido o processo de encomenda.
Aconselhava seriamente a uma revisão da usabilidade do vosso site.

Com os melhores cumprimentos,

Bruno Silva

Foram simpáticos o suficiente para responderem a pedir desculpas e a dizerem que se encontravam com “problemas técnicos”… Era o que esperava, mas pelo menos despejei a frustração!

Também achei curioso dizerem que estavam totalmente disponíveis para mais esclarecimentos, e de seguida me fecharem o ticket no sistema deles. lol

As promised, the public betas of the latest version of the Windows Live suite of PC applications are now available for download.  Go to http://download.live.com/ and get the newest Messenger, Mail,Photo Gallery, Movie Maker, Writer, Toolbar, and Family Safety.

in Windows Live Wire

So far I’ve only tested Windows Live Messenger, generally I like the new look. I love the "Favorites List" feature, since I already had a favorites group in previous versions of Windows Live Messenger. Another feature that may become useful: creating groups of users as a single contact. This way in a single click you can begin a conversation with multiple contacts, almost like a mailing list or a chat room channel.

Something I would like to change is the size of the avatars in the conversation window. It is pretty cool that now you can get a minimalistic conversation window if you hide the toolbar in the top and the avatars.

Make sure you restart your operating system after installing, because I was getting some strange window behavior previous to that. One feature that is a "little" buggy is the theme customization. You can try to change your windows color to black, but even if you set it as your default color, after restarting Windows Live Messenger it will be reset to the default blue, even the main window will get the default color…

Next step: keep on testing and try the other applications also.

This release represents the beta of Microsoft XNA Game Studio 3.0, which enables hobbyists, academics, and independent game developers to easily create video games for Windows and the Microsoft Zune digital media player using optimized cross-platform gaming libraries based on the .NET Framework.

The XNA Game Studio 3.0 Beta is a chance to get an early look at XNA Game Studio 3.0, and provide feedback on the product that is currently in development.

in XNA Creators Club

Now it supports Zune with the 3.0 software version. The CTP version didn’t have support for XBOX 360 development, now it is fully supported Finally we can use Visual Studio 2008 for XBOX 360 development! Other features that please me are the Rich Presence support (that message in XBox Live that tells you what are your friends playing in the context of a game. eg: level, dificulty,etc.), and Invites for joining you in a multiplayer game.

It contains a sample of a WCF service that uses LINQ to SQL to retrieve some data from a SQL Server Database (AdventureWorks) and return it as XML. I’ve also some commented code in order to add a JSON endpoint.

Download Source Code

In your Silverlight project, if you try to open directly the XML file using something like XDocument.Load(”Data.xml”) Silverlight will try to find the file inside the XAP file. We could place the XML file inside the XAP file in order to make it work, but when we needed to update the file we would have to change the XAP file (replacing an XML file in a ZIP file)… Instead, we will use an external XML file. We must download the file using a WebClient (the download term applies: remember that Silverlight code runs in the client side, so while accessing you website resources you are accessing remote resources).

The download is asynchronous, so we need to create an event handler to be executed when the XML file download is completed. The XML file is downloaded as a string, so we need to parse it into a XDocument object, in order to manipulate it. The example bellow shows a little bit of LINQ to XML. LINQ (Language Integrated Query) allows you to query several data sources, including XML, Databases, Object collections, etc (even Amazon…). A nice tutorial about LINQ to XML can be found at Scott Guthrie’s blog.

We iterate through the data points present in the XML file and create a list of pairs containing the labels and respective values. After building the dataPoints list, the remaining code is similar to the code I’ve shown you in the Part 1 of these tutorials.

The next and final step will be to use a WCF web service to retrieve the data from an database in order to create a real dynamic chart powered by Silverlight.

Download Source Code