FormatCommand throws exception if args[] has object with NULL value

Had a single OUTPUT SqlParameter in a query, which was left uninitialized (value=NULL), then LastCommand threw an exception because _lastArgs in DoPreExecute() created an object[0] containing NULL, which was not catched by FormatCommand() in "if (args != null && args.Length > 0)". Fixed it on my side by setting the value of the return parameter to 0, but raising issue in case you want to check _lastArgs creation.