You can overwrite your MainWindow.xaml file with this code without dragging the PdfViewerControl control to the window. In this case, you need to manually add references to the following libraries.
Right-click References in the Solution Explorer and select Add Reference… in the invoked context menu to add library references. Refer to the Redistribution and Deployment article for a full list or required assemblies.
Use the Assembly Deployment Tool to collect all assemblies that may be required for your application.
If you need to copy references locally, you can find copies at C:\Program Files (x86)\DevExpress 19.2\Components\Bin\Framework\
Load a document into the PDFViewerControl. You can do this in XAML using the DocumentViewerControl.DocumentSource property. Documents can be loaded from a stream, byte array or from a location specified by the full file path or Uri.
The following code snippet uses a pack Uri as a document source to load a sample document that was added to the root of current project as a resource file: