Handle Attributes and Methods Reference

This section contains reference entries that describe each handle attribute, handle method, COM object property, and COM object method that ABL supports. Handle attributes and methods, and COM object properties and methods, are all mechanisms that allow you to monitor and control the behavior of ABL handle-based objects (including widgets), system handles, and COM objects.

Each handle-based object has a set of attributes and methods (referred to generally as handle attributes and handle methods). Each COM object also has a set of properties and methods. This section describes every handle attribute and method available in ABL, but describes only the COM object properties and methods that directly support the ActiveX control container technology in ABL. All other Automation objects and ActiveX controls that you access from ABL provide their own COM object properties and methods. For more information on these properties and methods, see the documentation that comes with each COM object.

In this section, names of handle attributes and methods appear in all-uppercase, while names of COM object properties and methods, which follow Visual Basic coding conventions, appear in mixed case.

This section begins by explaining the syntax for handle-based object references. The basic syntax is similar for both handle-based and COM objects. However, it has been extended for COM objects to support the unique features of Automation objects and ActiveX controls. This extended syntax for COM object references follows in a separate section.

The descriptions that follow refer to both compile-time and run-time behavior, features that the language generally supports and determines at compile time and actions directed by using these features at run time. When describing compile-time features or actions, this section references ABL or the ABL compiler. When describing ABL-directed actions taken at run time, this section references the ABL Virtual Machine (AVM).

Notes: In character interfaces, all handle attributes and methods that reference pixels (for example, the HEIGHT-PIXELS attribute and the GET-TEXT-HEIGHT-PIXELS method) use a system default pixel value for the equivalent value in characters.

Properties and methods of classes are conceptually analogous to but different from either handle attributes and methods or COM object properties and methods. Class-based properties and methods participate in class hierarchies that you typically define, extend, and instantiate as objects of a user-defined class or interface type. All handle attributes and methods are associated with ABL handle-based objects, and are entirely defined and made available by ABL. COM object properties and methods are associated with pre-defined COM objects (Automation objects and ActiveX controls). The syntax for accessing all types of attributes, methods, and properties is very similar, but differ depending on the type of object with which they are associated. This section describes how to access the attributes, properties, and methods of respective ABL handle-based objects and COM objects only. For more information on accessing properties and methods of a class-based object, see the Class-based property access and Class-based method call reference entries.