Select with distinct in api collection

I am trying to load a collection using IEntitySource.GetCollection method. I need to have distinct values in this collection so I am trying to use Distinct() method after loading the collection. However, the next method should use an IEntityCollection. So, I need to have this distinct list in an IEntityCollection type.

Step 1 : GetCollection (This return an IentityCollection)

Step 2 : Fetch distinct values from this collection (Using Distinct() which returns IEnumerable type)

Step 3 : Do something to cast this object from IEnumerable to IEntityCollection)

Step 4 : Use the IEntityCollection for further operation ats the items under this collection would be of IEntity type.

The code read as :

DIm qry As Query = Query.From("TestTable") _

     .Where(Function(t) t.Column(Table.TestTable.OrderState) = "Test123") _

     .Select("TestKey")

Dim colTest As IEntityCollection = Nothing

colTest = Session.Source.GetCollection(qryTest).Distinct()

  1. This object colTest is returned as IEnumerable as Distinct is used, but I need to have this as of type IEntityCollection.