Replacing a standard lookup with our own

Sometimes we will need to add a field to a lookup or change the way it filters the list shown to the user. In this example, we will change the item lookup on the sales order line data source so that it only lists items that are on a related service order. This recipe will show you how to write a lookup, add a filter and an exists join, and prevent the standard lookup from being displayed.

We will be writing this lookup against a lookup event for the ItemId field on the SalesLine data source, on the SalesTable form.

How to do it...

To create a new lookup handler event, follow these steps:

1. Since this handles the lookup event on the SalesTable form, create a class named SalesTable_ConVehicleManagement_FormHandler...