ASP.NET MVC query lambda expression - sql

Question

Hello I have problem in one query. Why it's always return no value.
public List<UserDetail> userSearchModel(UserSearchModel searchModel)
{
string userid = User.Identity.GetUserId();
var user = _dbContext.UserDetails.Where(x => x.Id == userid);
var result = _dbContext.UserDetails.Except(user).ToList().AsQueryable();
if (searchModel != null)
{
if (searchModel.LanguageId.Count() != 0)
{
List<UserDetailLanguage> usrDetails = new List<UserDetailLanguage>();
foreach (var item in searchModel.LanguageId)
{
var details = _dbContext.UserDetailLanguages.Where(x => x.LanguageId == item).ToList();
foreach (var item2 in details)
{
usrDetails.Add(item2);
}
}
result = result.Where(x => x.UserDetailLanguages == usrDetails);
}
}
return result.ToList();
}
I want to get results which are the same in usrDetails list and in result.UserDetailLanguages.
In result.UserDetailLanguages I have record equals to record in usrDetails but this not want retrieve.
Here is my model:
public class UserDetail
{
public UserDetail()
{
this.UserDetailLanguages = new HashSet<UserDetailLanguage>();
}
[Key, ForeignKey("User")]
public string Id { get; set; }
public DateTime Birthday { get; set; }
public string Sex { get; set; }
public string Country { get; set; }
public string About { get; set; }
[NotMapped]
public int Age { get { return DateTime.Now.Year - Birthday.Year; } }
public virtual ApplicationUser User { get; set; }
public virtual ICollection<UserDetailLanguage> UserDetailLanguages { get; set; }
}
public class UserDetailLanguage
{
public Int32 Id { get; set; }
public virtual UserDetail UserDetail { get; set; }
public string UserDetailId { get; set; }
public virtual Language Language { get; set; }
public Int32 LanguageId { get; set; }
public Boolean IsKnown { get; set; }
public static implicit operator List<object>(UserDetailLanguage v)
{
throw new NotImplementedException();
}
}
public class Language
{
public Language()
{
this.UserDetailLanguages = new HashSet<UserDetailLanguage>();
}
public int Id { get; set; }
public string Value { get; set; }
public string Name { get; set; }
public virtual ICollection<UserDetailLanguage> UserDetailLanguages { get; set; }
}
What I'm doing wrong?

Answer 1

If you want to see if your value is in a list you use the Contains function of the list -- like this:
result = result.Where(x => usrDetails.Contains(x.UserDetailLanguage));
If you want to see if there are any items in both lists you can use intersection like this:
result = result.Where(x => usrDetails.Intersect(x.UserDetailLanguage).Count() > 0);

Answer 2

Looks like you are checking equality between lists in following code
result = result.Where(x => x.UserDetailLanguages == usrDetails);
This might not work, to check equality for lists you can use something like
Enumerable.SequenceEqual(FirstList.OrderBy(fList => fList),
SecondList.OrderBy(sList => sList))