Beginning Web Development, Silverlight, and ASP.NET AJAX

CHAPTER 15 ■ ENHANCING THE WEB EXPERIENCE WITH SILVERLIGHT 371
As you can see, the xamlFragment is a string containing a new piece of XAML. This is
created and a reference to it returned to the textBlock var. This reference is then added to
the tree by adding it to the children of the root element.
The findName Method
XAML nodes may be named using their x:Name attribute. Should you want to manipulate
the content of the XAML node (to, for example, change the contents of a TextBlock), you
do so by using the findName method to get a reference to that node, and then editing the
reference.
This was shown in our first example, in the event handler for clicking the TextBlock.
Here’s the code again:
var SilverlightControl;
var theTextBlock;
function handleLoad(control, userContext, rootElement)
{
SilverlightControl = control;
theTextBlock = SilverlightControl.content.findName("txt");
theTextBlock.addEventListener("MouseLeftButtonDown", "txtClicked");
}
function txtClicked(sender, args)
{
theTextBlock.Text = "Hello to you too!";
}
As you can see in the handleLoad function, the findName method was called to get a
reference to the TextBlock (called txt). This reference was then manipulated by adding an
event handler to it.
The createObject Method
This method allows you to create a new object for a specific purpose. In version 1.0 of
Silverlight, only one object is supported: the Downloader object. The Downloader object
allows you to download additional elements using asynchronous downloading functionality.
It is very similar in scope to Ajax. It supports a number of properties, methods, and
events that allow you to handle the download.
Using the Downloader Object
The Silverlight control provides a Downloader object (created using the createObject
method) that allows you to get additional application assets in an asynchronous manner.