Described is a system and method for controlling user interface (UI) properties with data. An application is separated into independent parts, a logic portion and a UI portion. The logic portion manipulates data values within the application. The UI portion is responsible for displaying UI properties. A binding specification describes a relationship between the UI property and the data value. The binding specification is used by system level code to determine the manner in which it is notified when the data value undergoes a change and the manner in which it directs the UI portion to reflect the change in the UI property. The binding specification identifies a source data item, a path to the data value in the source data item, a target UI element, and the UI property on the target UI element. The binding may be specified using code or markup language.