Conversion Tool
During the migration process each element in the original PowerBuilder application is transformed into its C# equivalent, as in the following:
Powerbuilder Target (.pbt) is transformed into a Project Solution file (.sln)
PowerBuilder Library (.pbl) is transformed into a Project file (.csproj)
PowerBuilder classes are each transformed into a separate class and also an associated interface which is used by WebMAPS's type resolution mechanism.
As shown in the image below; there are two additional projects that are added to the migrated solution: the first one is called AllInterfaces and it holds all of a set of interfaces which are related to each PowerBuilder object, and the second one is a Web Project which has the same name as the original PowerBuilder target and is used to deploy the web application on a server.
Migrated solution
A solution is a workspace used to handle multiple projects related to each other. In a migration, the solution contains all of the migrated project libraries used by the original application plus the AllInterfaces and Web Site projects.
AllInterfaces
In order to replicate the PowerBuilder's library reference handling, a project called "AllInterfaces" is created by the conversion Tool, which contains a set of Interfaces related to each class in the original source code, including visual controls, simple classes, structures, etc.
The main purpose of this mechanism is to avoid possible circular references between project libraries. These kinds of references tend to be common in native PowerBuilder code; however they cannot be resolved using traditional .NET library dependency resolution.
The image below shows the dependency project libraries and the interfaces project. Each Library reference has a reference to AllInterfaces. Project libraries have no implicit references between themselves since rresolution is handled by the WebMAP's custom type resolver.
Application Projects
The application projects are generated directly from the original PowerBuilder Libraries. A C# project is created for each PBL in the source application. Every project contains an equivalent class for the original PowerBuilder object. The object transformation equivalents are the following:
Custom and Standard classes and Structures are transformed to: a C# class and an interface
Custom, External and Standard Visuals, Menus and Windows are transformed to a C# class split into two different files and an interface
DataWindows are transformed into a single C# class.
For some components (mostly visuals) the transformation results into the generation of two class files: One (class.cs) containing logic and functionality, and a second (class_Layout.cs) that contains the visual representation of the window.
Application Site Project
This project is a standard ASP.NET Core Web Application project that is used as the entry point for the migrated solution. It also serves as a container for all of the project libraries in order to solve the original libraries' references as shown in the image below.