I just simple know that is a published project, but how to open that file as a project? Here is the story, I got a file from a contractor with all the project and the pages and I would like to check the code and run the project from Visual Studio 2017.
Sorry about my ignorance and thanks in advance.
You can't.
What you can do though is create an ASP.Net Project (e.g. .csproj) and then right-click on a folder or the root of that Project and select "Add Existing Web Site...". This adds your site to that solution.
Note that .publishproj projects ("Web Site" Projects, aka "Web Applications") are not really compiled/built. (Though they can be pre-compiled, but that's not the same thing).
Web Sites are "published" not "built". Note that publish profiles (.pubxml) files are stored in /App_Data/PublishProfiles folder and work very much the same as .csProj files. In fact MSBuild will recognize some of the same elements, such as <task> and <using>. You just have to manually add them.
