How to build a .net application without a .csproj file?

Question

.NET

an old project, and there is no file with the .csproj extension, there are a lot of folders with source code, and they should probably be assembled into dll and exe somehow, but I can’t find anything similar to the description of such an assembly

Answer 1

This is done using csc.exe
Well, or through mono (mcs) - it depends on what kind of project.
Once upon a time there was nant - the progenitor of msbuild.
It also has its own project model and build files

Answer 2

Create a project in Visual Studio and add all your files to it. And collect in the studio.