Windows Presentation Foundation
This section under construction.
Windows Presentation Foundation (WPF) is a library used to create the user interface for smart client applications. Importantly, WPF separates the designer from the developer by having files that describe the user interface and then code files, written by developers, that utilize them.
Simply put, XAML describes the user interface.
Understanding XAML (eXtensible Application Markup Language) is key to understanding WPF. Some .NET applications (and others like Xamarin) utilize XAML during their development. XAML code is declared using textual XML.
WPF extenstions to XAML are defined with the XML namespace
The XML namespace
http://schemas.microsoft.com/winfx/2006/xaml is mapped to the
x prefix (to be seen) and
features that are common to all XAML vocabularies.
XAML elements map to .NET classes.
XAML elements map to custom .NET classes, too.