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Usually the order of elements in a collection is something one does not feel to be important. We have plenty of methods in the Framework to order things and now that there is LINQ to Objects the need to sort something is really matter of seconds.

Since the introduction of LINQ the main problem is that you have many cases where a few lines of code are adding really complex iteration logic and often this hurts performances when the count of milliseconds is something important.

Imagine you have a long task to accomplish and need to get updates from the webserver that is running the activity. This task may be an import or parsing of a complex file.  Doing this activity with a normal page or with a webservice may incur in timeouts and obviously leave the user waiting the end of the task without a visible notification

One of the recurrent questions people ask me in the forums is about the applying of security constraint to the applications being developed. The last releases of useful tools like WCF Ria Services added the capability of bringing the security context from the server to the plugin running into the browser. This let the developer to have the current logged-in user and his roles available to apply rules to elements of the user interface.

With WCF Ria Services you can create easily an AuthenticationDomainContext and when you make a reference to it from a Silverlight project you will have available a class named WebContext.

I think some of you may have developed an application that requires a lot of roundtrips on the server to retrieve data to be displayed to the user. Every time your application goes to the server it may have to wait for long running query to end its works, perhaps because the data are extracted from an huge database. Then it have to download the data and finally display them onto the screen.

If you have already deal with this kind of interaction you should know that the two connection limit of the web browser can become evident. For some of you that are not aware of this limitation you have to know that due to the RFC 2616 specification, the compliant browsers have not to hammer the network and are limited to make only two simultaneous connections to the server (per domain).

In the previous part of this article I introduced a custom Form control I made for some real world projects. I've briefly explained the reasons why I choose to not use the Silverlight Toolkit's DataForm, just before to show how to build this control, and I've also detailed what I like of the DataForm and what I should retain in my Form control.  One of this features is the validation of the input and it is what I'm about to describe in the second part.

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The databinding in Silverlight directly supports the validation through a couple of attributes, that let the developer specify if the markup extension has to notify validation exceptions to the control binded to a property so it can show the errors to the user.

Working with DataForm I found difficult to use it in many scenarios due to its design. So I've created a control where I do not generate fields but I handle automatic validation and cancel/commit commands enabling also the usage of the control in mvvm scenarios. This is a good starting point to understand about Validation, BindingExpressions and traversing the visual tree.

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The first time I've met the DataForm control - it was some days after its beta release in the Silverlight Toolkit - I was really astounded from its power. It is capable of many wonders: it generates fields detecting the properties of the binded item, it automatically validates the input values using a bunch of attributes in a way similar to ASP.NET Dynamic Data, it manages the workflow passing through Edit, ReadOnly and Insert state, and these are only a small subset of the features it exposes.

Read part 2 of this article series called: A simplified DataForm replacement - Part 2 Adding validation support

This interview is the first one from our 'Featured Author' interview series. We'll be presenting you the major contributors to the article content on SilverlightShow - Silverlight MVPs, bloggers and enthusiasts willing to share their experience and knowledge with the rest of us.

In this interview we'll be talking to Andrea Boschin - a Silverlight MVP with over eleven years of experience in IT, and a frequent speaker at Silverlight events in his country.

Q. Andrea - please briefly introduce yourself, and your experience with Silverlight.

A. I’m a guy 41 years old from Italy and currently I live and work in Treviso, a beautiful town near Venice. I started to work in the IT relatively late after doing some various jobs like graphic designer and school teacher. Finally I started to work into the web and learned by myself to program in VB and ASP and later in C# and ASP.NET. Since the start of my work, I’ve found I like to learn new technologies and take them into the real world. This happened with ASP.NET, the source of my first two MVP awards, and recently with Silverlight, I have started to use from the v1.0 in some real projects.

During a recent work I found some trouble working with the TreeView control in a Model-View-ViewModel scenario. As usually happen, the standard controls are designed to work in an event-driven behavior and this non always marries with a correct MVVM implementation. After some work, I found a way to change the TreeView and transform it to be lazy loadable.

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The Model-View-ViewModel pattern has been introduced in Silverlight by few time and this platform lacks a complete support to the pattern by the standard controls.

The new release of Silverlight has silently introduced some new improvements to the DataBinding that
bring the RIA platform closer to WPF for some aspects, and at the same time strongly simplify the development
of data driven applications. In this article we will explore deeply these new features.

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Since the first release of WPF, the DataBinding was one of the most important and appreciated features of this platform. This is due to its powerful capabilities and its simplicity that let the developer create complex interfaces with a few lines of codebehind moving many thing to declarative programming in XAML.