Previously in this chapter, we saw that LiveBindings expressions allow you to access the main subject of the expressions (through the Self variable) to access its properties (that is, the Owner property, to access the underlying TDataSet of a TField component). You've also learned how to call methods using the same notation and expression engine. This mechanism is generic enough that you can usually reach the form (or frame or data module) you have put your BindSource on. This implies you are actually able to reach, for example, your form object (through the ownership chain) and call one of the methods of your form object within a LiveBindings expression.
If you have an expression that you need to bind to a field of a dataset (exposed through a TBindSourceDB component), you are in a situation where you can use the following:
- Self: This references an instance of TField.
- Self.Owner: This references the instance of TDataSet that is the owner...