You must use List, not EntityList.
Try using a List<PayrollTrxLines> instead of an EntityList<PayrollTrxLines> as in this example from Reference Help
PersistenceManager pm = PersistenceManager.DefaultManager;
// Retrieve all customers.
EntityList<Customer> allCustomers = pm.GetEntities<Customer>();
System.Diagnostics.Debug.WriteLine(allCustomers.Count.ToString());
// Define find criteria - this looks for companies beginning with letter 'A'.
Predicate<Customer> filter = delegate(Customer pCustomer) {
return pCustomer.CompanyName.StartsWith("A");
};
// Find a subset of customers.
List<Customer> AListCustomers = allCustomers.FindAll(filter);
Console.WriteLine(AListCustomers.Count.ToString());