Data binding in WPF is always comprises two objects, the binding source and the binding target, where the source represents the object that provides the data and the target represents the UI element or property that expose the data value. Figure 7-1 shows a basic representation of this mechanism.
Figure 7-1. WPF data binding mechanism
In Figure 7-1 you can see three major actors involved in the data binding process:
INotifyPropertyChangedinterface, an interface that uses an event to notify when the value of a property has been changed.