I am not clear about T-SQL error severity levels as they relate to the System.Data.SqlClient library in .NET client applications. [bolded for emphasis in response to close-vote suggestion that I clarify how an answer about what severity levels "mean" does not address my question].
Which T-SQL error level(s) would allow the T-SQL statement to continue but would cause the front-end to display the message?
I thought it would be level 10 but that does not display a message in the front-end application; the docs say
For compatibility reasons, the Database Engine converts severity 10 to severity 0 before returning the error information to the calling application.