SubSonic How to provide a column name in a generic method - subsonic

Question

Using SubSonic3, I have this generic method (thanks to linq guy, James Curran):
public List<T> GetFromList<T>( List<Guid> _IDs,
Func<T, Guid> GetID,
Func<IQueryable<T>> GetAll )
where T : class, IActiveRecord
{
List<T> rc = null;
var Results =
from item in GetAll( )
where ( _IDs as IEnumerable<Guid> ).Contains( GetID( item ) )
select item;
rc = Results.ToList<T>( );
return rc;
}
It is called with something like
List<Job> jresults = GetFromList( IDList,
item => item.JobID,
( ) => Job.All( ) );
Where IDList is a List of guids that are keys to the table.
When not generic, the linq looks like this and works perfectly. I was quite impressed that SubSonic's linq provider could take this code and turn it into SELECT * FROM Job WHERE JobID IN (a, b, c):
var Results =
from item in Job.All( )
where ( _IDs as IEnumerable<Guid> ).Contains( item.JobID )
select item;
I want to be able to call this method on tables other than Job, with keys other than JobID. The GetAll Func works because it returns the same IQueryable that Job.All( ) does, but GetID throws a run-time exception, "LINQ expression node of type Invoke is not supported". GetID returns a value, but what I really need from it is something that Contains( item.JobID) would recognize as a column name and that the "where" syntax would accept. (I don't show it here, but I have the same problem with orderby.)
Is that possible, with what you know of SubSonic3?

Answer 1

My solution was to pass in the expression that Where needed:
public List<T> GetFromList( List<Guid> _IDs,
Func<IQueryable<T>> GetAll,
Expression<Func<T, bool>> _where )
where T : class, U, IActiveRecord
{
List<T> rc = new List<T>( );
if ( 0 < _IDs.Count )
{
if ( MAX_ITEMS > _IDs.Count )
{
var Results = GetAll( ).Where( _where );
rc = Results.ToList( );
}
else
{
var Results =
from id in _IDs
join item in GetAll( ) on id equals item.KeyValue( )
select item;
rc = Results.ToList( );
}
}
return rc;
}
called by
rc = GetFromList(
IDList,
( ) => Job.All( ),
( item => ( IDList as IEnumerable<Guid> ).Contains( item.JobID ) ) );