Professional Visual Basic 2012 and .NET 4.5 Programming

The XAML Markup Language

XAML stands for eXtensible Application Markup Language. It's pronounced “xammel,” rhyming with “camel.”

Most of the XAML in your applications will be produced by visual designers. However, it is sometimes necessary to edit XAML directly, and you also need to understand the role that XAML plays in your application. Consequently, in this chapter, XAML will be presented as bare markup language, with no reference to the visual designers. Chapter 13 will introduce the visual designer specifically for Window 8 XAML applications.

XAML is XML with a certain schema. You can edit it with any text editor, as long as you produce valid XAML. But like all XML, it's tedious to edit, which is why you'll want to use visual designers whenever possible.

There's nothing magical about XAML. Anything that's possible in XAML is also possible in code, though the XAML is often more compact and easier to understand.

Strictly speaking, XAML isn't just for user interfaces. Windows Workflow uses XAML to describe workflows, for example. However, for simplicity in this book, XAML will be discussed solely as a user interface technology.

A Sample Page of XAML

A page of XAML describes a set of instances of .NET classes. It includes property settings for those classes, and how the classes are grouped together. The grouping takes the form of a logical tree. There is a root element, which contains other elements. Those elements may then contain sub-elements, and so on.

Here's an example to ...