Importing XAML namespaces

One of the basic features of XAML is the ability to import namespaces so that you can use controls or classes that aren't included in a basic framework but come from a class that belongs to a custom namespace (it could be part of your project, an external class library, or a NuGet package). Namespaces are declared at the top-level container, typically the Window class or the Page class.

In WPF, you use the following syntax to declare a namespace:

<Window x:Class="MyApp.MainWindow"
      xmlns="http://schemas.microsoft.com/winfx/2006/
        xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/
        xaml"
      xmlns:d="http://schemas.microsoft.com/expression/
        blend/2008...