how to compare two connection string in sql server

Question

sir i have two database one is connection string (year 2014-2015 ) && second is (year 2015-2016) the user select 2014-2015 the open database (year 2014-2015) connection string the user select 2015-2015 the open connction string is 2015-2016 how can possible in public class c# code