XAML—XAML Compilation

Visual C# Tutorials

.NET Framework Tutorials

XAML Understanding XAML § pre-WPF GUIs XAML Variants XAML Compilation XAML Basics § Properties and Events § Use Other Namespaces Loading and Compiling § The Last Word

© 2007 Matthew MacDonald

XAML Compilation

The creators of WPF knew that XAML needed to not just solve the problem of design collaboration—it also needed to be fast. And though XML-based formats such as XAML are flexible and easily portable to other tools and platforms, they aren’t always the most efficient option. XML was designed to be logical, readable, and straightforward—not compact.

WPF addresses this shortcoming with BAML (Binary Application Markup Language). BAML is really nothing more than a binary representation of XAML. When you compile a WPF application in Visual Studio, all your XAML files are converted into BAML and that BAML is then embedded as a resource into the final DLL or EXE assembly. BAML is tokenized, which means lengthier bits of XAML are replaced with shorter tokens. Not only is BAML significantly smaller, it’s also optimized in a way that makes it faster to parse at runtime.

Most developers won’t worry about the conversion of XAML to BAML because the compiler performs it behind the scenes. However, it is possible to use XAML without compiling it first. This might make sense in scenarios that require some of the user interface to be supplied just in time (for example, pulled out of a database as a block of XAML tags). You’ll see how this works later in this chapter, in the section "Loading and Compiling XAML".