Introduction

If you need to use the XpsDocument class in your WPF project, you must add a reference to System.Windows.Xps.Packaging namespace. However, the assembly in which this namespace is defined is not a part of a WPF application by default. It is defined in the ReachFramework.
To add a reference to ReachFramework, you right-click on Add Reference on the project name in Solution Explorer. On the .NET Framework, select ReachFramework and other assemblies from the list and click OK button. Figure 1 shows ReachFramework in Add Reference dialog.
reachframeworkimg.jpg
Figure 1
After adding this reference, you should be able to use XpsDocument in your WPF applications.