XAML is an XML-based markup language that can be used to declaratively program the Windows Presentation Foundation object model.
It is especially useful for application user interfaces.
Each XAML tag corresponds to an object model class. A tag also usually has a collection of attributes that corresponds to the properties of the tag's associated class. At compile time, the parser converts the XAML into a partial class that contains equivalent procedural code. Each XAML tag becomes an instance of the corresponding object model class, and the tag's attribute values are assigned to the corresponding object properties. Then the partial class that is created from the parsed XAML is combined with the page's code-behind file by the common language runtime compiler to create an object for the page.