如何将UserControl加载到(WPF)窗口中的ContentPresenter中?

I have a window that contains a Viewbox. In that Viewbox, I would like to have one of several views which I have already created as UserControls. I am using the MVVM (Model View View-Model) design pattern. I have searched for about an hour online, and I cannot find any examples or tutorials that explain how to display a UserControl using a I have a window that contains a Viewbox. In tha