map table to itself in Parent-Child relationship Fluent Nhibernate

I have situation where I am mapping table's columns to the primary key of same table. The table looks like this

---+-------+---------
ID  Name    ParentId
---+-------+---------
1   Parent1  0
2   Child 1  1
3   Child 2  1
4   Parent2  0
5   Child 3  4

I have created a following Model and Fluent NHibernate mapping class

//Model.LocationType.cs
public class LocationType
    {
        public virtual long Id { get; set; }
        public virtual string ShortName { get; set; }
        public virtual string Description { get; set; }        
        public virtual IList<LocationType> ParentId { get; set; }
    }

and

//Mapping.LocationTypeMap.cs
public class LocationTypeMap : ClassMap<LocationType>
    {
        public LocationTypeMap()
        {
            Table("SET_LOC_TYPE");
            Id(x => x.Id).Column("LOC_TYPE_ID").GeneratedBy.Assigned();
            Map(x => x.ShortName, "SHORT_NAME").Length(15).Not.Nullable();
            Map(x => x.Description, "LOC_DESC").Length(50).Not.Nullable();
            References(x => x.ParentId).Column("PARENT_LOC_TYPE_ID").Cascade.SaveUpdate();
        }
    }

but I am receiving follow error message when i execute my code:

Unable to cast object of type 'SmartHRMS.Core.Domain.Model.LocationType' to type 'System.Collections.Generic.IList`1[SmartHRMS.Core.Domain.Model.LocationType]'. 

Edit 1: Instead of using i tried

HasMany(x => x.ParentIds).KeyColumn("PARENT_LOC_TYPE_ID");

Although it worked and solved the casting problem that I mentioned above but the result I am gettting is the reverse of what i need.开发者_运维问答 In parent's LocationType objects, it lists all childs in IList, so for above example the result will be:

-----+----------+------
ID     Name       ParentId
-----+----------+------
1     Parent1     IList<Child1, Child2>
2     Child 2     IList<Empty>
3 .... same
4     Parent2     IList<Child3>
5     Child 3     IList<Empty>

---

Seems like you should use HasMany in your mapping instead of References.