Microsoft Visual Studio Community 2022 (64-bit) - Version 17.9.7

Question

I am using C# from the above.

For a simple one file console app, I get a compile error saying "ProgA (namespace) already contains a Program class." It does not - there is just 1 file with a single definition internal class Program put there during file creation. There is a similar message for Main.

Why does C# think these have been duplicated.

Answer 1

You don’t show your code, nor identify the .net version. so we can only guess. See rules for defining Main and determine which one you broke, though you appear to have defined the class Program twice.

https://learn.microsoft.com/en-us/dotnet/csharp/fundamentals/program-structure/main-command-line