A solution can contain multiple projects. Working with multiple projects is not much different than working with a single project. Use the Solution Explorer to navigate between the projects in the current solution.
You might add a project to a solution to copy code between projects. You might want to reference the procedures, functions and classes in one project and use them in another project. By adding multiple projects to a single solution, it allows you to use a project as a set of common utilities that you might use with more than one project.
Projects can be unloaded from a solution when they are no longer needed. If you no longer want a project to load with a solution, you can unload the project and then reference the compiled DLL assembly of the project instead. Working with the compiled DLL helps to prevent accidental edits to the source code.
To add a project to a solution
Add
New Project to create a new project and add it to the current solution.
Add
Existing Project to display the Add Existing Project dialog box and add an existing project to the current solution. In the Add Existing Project dialog box, browse to and select the project to add to the current solution. To unload a project from a solution