Linq query getting null value

 var selection3 = VSANDictionary
                 .SelectMany(vsan => vsan.Value.ActiveZoneset.ZoneList)
                 .Select(z => z.ContainsMemberWWPN(zonemember))
                 .Where(m=> m != null)

string RoleName = (from Users in db.Users
join UserRoles in db.UsersInRoles on Users.UserId equals UserRoles.UserId
join roles in db.Roles on UserRoles.RoleId equals roles.RoleId
select roles.RoleName

string RoleName = (from Users in db.Users
join UserRoles in db.UsersInRoles on Users.UserId equals UserRoles.UserId
join roles in db.Roles on UserRoles.RoleId equals roles.RoleId
where Users.UserId == UserId
select roles.RoleName);