I have been re-factoring one of my old MSSQL Connection helper library and I got the following error:
Severity Code Description Project File Li
You have a constructor which takes 2 parameters. You should write something like:
new ErrorEventArg(errorMsv, lastQuery)
It's less code and easier to read.
EDIT
Or, in order for your way to work, you can try writing a default constructor for ErrorEventArg which would have no parameters, like this:
public ErrorEventArg() {}