troubles with server logins and database users
Database obj = new Database(new Server(@"ADMIN-PCMSSQLSERVER2"),"ShoppingMall");
 bool user = obj.IsMember("db_owner");

string connection_string = @"Data Source=ADMIN-PCMSSQLSERVER2;InitialCatalog=ShoppingMall;User ID=ttt;Password=ttt";

Database db = new Database(new Server(@"ADMIN-PCMSSQLSERVER2"),"ShoppingMall");
User user = new User(db, "ttt");
bool isMember = user.IsMember("db_owner");