MetaDraw is available as either ActiveX or .NET WinForms component for creating drawings, diagrams, image annotations. MetaDraw has optional DXF support (import and export) making it possible to display and convert 2D CAD drawings for example from AutoCAD. I was able to save a complex drawing in AutoCAD 2010 to DXF 2010 format and view and edit it with MetaDraw.
If you have the need to display images in raster or vector format, convert between formats, support zoom and pan, edit and add labels, annotations and the like MetaDraw is worth looking at.
With MetaDraw you can include basic CAD functionality in your software like editing objects and even have links between object making it easy to make diagrams. The API is extensive so you can do quite a lot of things with it. Several code examples are available and together with the documentation you should be up and running quickly.
The MetaDraw product have been around many years continually being improved upon. The latest version when writing this was released in March 2009. I tested using Visual Studio 2008 and Windows Vista as well as Windows 7.
This animated GIF is created when I try one of the sample applications that shows the functionality to link objects.
MetaDraw .NET 2.0 is a 32-bit DLL so it can not be used in 64-bit applications even though it can be used in 64 bit environments if the application is 32-bit.
Disclaimer. I was offered a free license with no strings attached.