public IHttpActionResult CreateUser([FromBody] UserTable userObj) { UserTable existingUser = userdetails.Get(userObj.UserEmailId); try { if (!ModelState.IsValid) { return(BadRequest(ModelState)); } if (existingUser != null) { return(BadRequest("Email already exists")); } if (userObj.Age < 18) { return(BadRequest("Age cannot be less than 18")); } userdetails.Add(userObj); } catch (Exception ex) { throw ex; } return(Ok(userObj)); }