Implementing an OpenEdge GUI for .NET does not mean that you have to rewrite your application code. You should review your application architecture and decide which, if any, components could be modified to take full advantage of the Ultra Controls and the underlying object-oriented extensions to ABL. Materials on Progress Communities and presentations given at Exchange user conferences and other mediums over the past several years have described an approach to building applications called the OpenEdge Reference Architecture (OERA). Most of those existing materials focus on the data management side of an application, describing data management components such as Business Entities that encapsulate access to a particular set of related application data.