MVC one to many user companies and notifiaction - asp.net

Question

I have three tables. Users Notification and Company. I have to made relation one to many which one user can have many notification from company. Notification have to be seen only for users from this company. Example users A company B can see notification only from company B not from the others. How to create query and check user which is actually logged in? Can you help me? I show the code.
[Table("Core.Powiadomienias")]
public class Powiadomienia : Entity
{
public string Tytul { get; set; }
public string Tresc { get; set; }
public long? Firma { get; set; }
public ICollection<User> Users { get; set; }
}
public class User : Entity, IUserIdentity, IAuditable, ILoggable,
IConfidential
{
#region User()
public User()
{
LockoutEnabled = true;
Roles = new List<Role>();
}
#endregion
public Guid PublicId { get; set; }
public DateTime DateCreatedUtc { get; set; }
public DateTime? DateModifiedUtc { get; set; }
public long CreatedBy { get; set; }
public long? ModifiedBy { get; set; }
public string UserName { get; set; }
public string Email { get; set; }
public bool EmailConfirmed { get; set; }
public string PasswordHash { get; set; }
public string SecurityStamp { get; set; }
public string PhoneNumber { get; set; }
public bool PhoneNumberConfirmed { get; set; }
public bool TwoFactorEnabled { get; set; }
public DateTime? LockoutEndDateUtc { get; set; }
public bool LockoutEnabled { get; set; }
public int AccessFailedCount { get; set; }
public bool IsAdmin { get; set; }
public string RolesGroupsXml { get; set; }
public string GivenName { get; set; }
public string Surname { get; set; }
public string JobPosition { get; set; }
public string HomeCity { get; set; }
public string HomeStreet { get; set; }
public string HomeHouseNo { get; set; }
public string HomeFlatNo { get; set; }
public string HomePostCode { get; set; }
public string HomeCountry { get; set; }
public long? FacePictureId { get; set; }
public virtual File FacePicture { get; set; }
public long? FirmaId { get; set; }
public Powiadomienia Powiadomienia { get; set; }
#region GetList()
public static IEnumerable<TResult> GetList<TResult>(IPager pager, string
tytul , string tresc = null, long? firma = null)
{
using (var context = Context.Read())
{
Slave db = new Slave();
var query = context.Query<Powiadomienia>().AsQueryable();
if (!String.IsNullOrEmpty(tytul))
{
query = query.Where(p => p.Tytul.Contains(tytul));
}
if (!String.IsNullOrEmpty(tresc))
{
query = query.Where(p => p.Tresc.Contains(tytul) &&
db.Firmy.Select(x => x.Nazwa).Equals(p.Firma));
}
if (firma.HasValue)
{
var value = String.Format("<item>{0}</item>", firma);
query = query.Where(p => p.Firma.HasValue);
}
return query
.Pager(pager)
.GetResult<TResult>();
}
}
public class UserService
{
#region GetList()
public static IEnumerable<TResult> GetList<TResult>(IPager pager, string
userName = null, string givenName = null, string surname = null, long? role
null, bool? isAdmin = null, long? firmaid = null)
{
using (var context = Context.Read())
{
var query = context.Query<User>().AsQueryable();
if (!String.IsNullOrEmpty(userName))
{
query = query.Where(p => p.UserName.Contains(userName));
}
if (!String.IsNullOrEmpty(givenName))
{
query = query.Where(p => p.GivenName.Contains(givenName));
}
if (!String.IsNullOrEmpty(surname))
{
query = query.Where(p => p.Surname.Contains(surname));
}
if (firmaid.HasValue)
{
var value = String.Format("<item>{0}</item>", firmaid.Value);
query = query.Where(p => p.FirmaId.HasValue);
}
if (isAdmin.HasValue && isAdmin.Value == true)
{
query = query.Where(p => p.IsAdmin == true);
}
return query
.Pager(pager)
.GetResult<TResult>();
}
}
#endregion