Select a valid startup item

Question

I switched from Visual Studio 2008 to VS 2017.

I get this error when trying to start a project with a green play button:

Obviously, I have to select a valid startup item, but for this I need two information:

1. What are the typical valid startup items that I can try to choose?

2. How can I choose them?

I have been working as a developer for a long time, but I am new to Visual Studio, so please give me instructions based on the terminology that I see on the screen.

Answer 1

You may have opened your project using

File->Open->Folder

Use the correct method to open a project using

File->Open->Project/Solution

or

File->Open->Website

Answer 2

> > . > . > .

Answer 3

I went to File> Open> project / Solution and found the file ".sln". I clicked on it and then opened it and it worked for me. Just spent ages trying to figure it out!

With respect,