Project files created with Microsoft Visual Studio are not specific to AutoCAD, but do contain specific project settings that you will need to be familiar with in order to create a DLL assembly file that can be loaded into AutoCAD. This guide discusses creating projects for Visual Basic® (VB) .NET and Visual C#® with and without the AutoCAD .NET Wizard.
A project is a collection of code and resource files; class modules, WPF windows, and Windows forms that work together to perform a given function. When a project is created, a solution is also created which contains the project you are creating. A solution is used to reference one or more projects. Usually you do not have to work with a solution directly unless you want to reference the exposed functionality of other projects.
An example of a multi-project solution is when you have a new project and an existing project that contain a set of methods, functions, and classes that you want to use with a new project.
A solution can contain any combination of VB.NET and C# projects. Using different types of projects in a single solution allows each developer to use the programming language of his or her choice.
Project and solution files have the following file extensions: