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A common scenario in data binding is to format the data displayed in the UI. Almost every time you show a date or a price you need to format it. Silverlight and WPF are using the so called converters to apply custom logic to a binding.

Using Converters

Let's make a small example that illustrates the problem. Consider a ListBox filled with client details - name and birthdate.

Here the ListBox is bound to a custom business object with a field Birthdate of type DateTime - pretty common situation.

Yesterday we've published Silvester - Silverlight Twitter widget and the idea was to let people put it on their blogs. To use the widget you need only an HTML snippet placed somewhere on your blog/profile page. The snippet contains an <object> tag that refers the widget's XAP file from our domain. So what you actually do is refer a resource from other domain, a.k.a x-domain scenario or cross-domain scenario.

Silverlight is a client technology and as such it sets a lot security requirements to keep the applications secure by default.

Are you a fan of Twitter? Personally I'm, but I'm also a fan of Silverlight. Twitter has a couple of Flash and HTML badges (a.k.a widgets) you can get and put on your blog to let your visitors know what you are up to in the moment. However, Twitter does not have a Silverlight widget. What negligence! :) If you are like me and want not a Flash, but a Silverlight widget on your blog go ahead and read on how you can build one by yourself or just copy the text below to use it.

I've been playing with some timers and Web Services and I got stuck in a case where the background thread was trying to update the UI. Well, that's never going to happen. To update the UI you should use the UI thread. Let's see how we can call the UI thread from the background thread.

Consider this situation:

You have data that needs to be updated every minute. The data is loaded by calling a web service.

For the update you can use the Timer class. Both the timer and the web service calls are executed asynchronously.

Introduction

In Silverlight there is a TextBlock control that is used to display simple text. However in many cases you need to display hyperlinks in the text. This article focuses on how to build such control and provides full source code for it.

LinkLabel source code

Overview

In this article I take for granted that you have basic understandings how to build a custom control in Silverlight. I described the main flow in a previous post so go read it if you need to fill some gaps.

Introduction

This articles focuses on the process of creating a Custom Control in Silverlight 2. It describes the basics of what you need to build a styleable control with custom logic that can be used in Silverlight applications. The article shows a sample(part) of implementing a LinkLabel control that recognizes URIs in a given text and displays them as links instead of as plain text.

Overview

The control model in Silverlight 2 offers creating UserControls and Custom Controls. UserControls enable encapsulation of a specific logic. They are used in scenarios where you want to reuse XAML and/or logic in multiple places or build a sophisticated page with smaller chunks(the UserControls). However, in other scenarios you may need a custom logic to be built in the control and this control to allow designers customize easily its look. You need a way to modify the control visuals without having to modify the control logic. This is where the Custom Controls comes in handy. In Silverlight they derive from the Control class and specify a default style for the way they will look like.

While playing with the ListBox control I want to set the ScrollViewer's VerticalScrollBarVisibility/HorizontalScrollBarVisibility properties in the XAML. The following code illustrates it:

<ListBox x:Name="StatusList" 
ScrollViewer.HorizontalScrollBarVisibility="Hidden"> 
    ...
</ListBox>

Everything looks just fine until you start the application and the XAML parser throws an exception: 

System.Windows.Markup.XamlParserException: Unknown attribute ScrollViewer.VerticalScrollBarVisibility on element ListBox

Actually you will experience this error every time you try to specify a control's attached properties in XAML.

Overview

Telerik, one of the most active component vendors in the last years, have already released a couple of Silverlight components. Read on what they share with us about the components we can expect, problems they faced and more.