I've never heard of this being supported, and the error you got would appear to indicate that it isn't. That is, that "CaseCollection" is not a mapped class.
Even if it were, it would be no more efficient than you iterating over the collection yourself:
Code:
public virtual Result Save(CaseCollection objCaseCollection)
{
try
{
this.OpenSession();
this.BeginTransaction();
foreach ( object o in objCaseCollection ) session.Save(o);
this.CommitTransaction();
return new Result(true);
}
catch (Exception ex)
{
this.RollbackTransaction();
return new Result(false, ApplicationManager.StackExceptionMessages(ex), ex);
}
finally
{
}
}