class Field example
The following example creates a calculated field, using the Field’s beforeGetValue event to calculate the total price from the quantity and price per item for each line item:
q = new Query()
q.sql := "select * from LINEITEM"
q.active := true
c = new Field()
c.fieldName := "Total"
q.rowset.fields.add(c)
c.beforeGetValue := {||this.parent["Quantity"].value * this.parent["PricePer"].value}
Because this refers to the Field object itself, this.parent refers to the fields array, through which you can access the other field objects.