A project with an Output type of Class Library cannot be started directly

Question

I\'ve download sample code with C#. but when I run I get this error message:

A project with an Output type of Class Library cannot be started direct

Answer 1

The debug settings of your Visual Studio development environment might be left blank. Please check if the following highlighted fields are missing, if they are missing then fill it up with your specific executable.

These fields are required to let the VS start the program for debugging. In the above picture, I'm developing a VSPackage so the:

1. The external program is devenv.exe
2. Command line argument is /rootsuffix Exp (for starting the experimental instance).

Note: I can assure you the answers mentioned in here didn't help me fix the issue because my project was already set as a startup project, now I came across an MSDN blog which helped me and lead to this answer.