Progress
Language Reference
Referencing COM Object Properties and Methods
A COM object property is a value that defines the visible, functional, and other characteristics of a COM object (ActiveX Automation object or ActiveX control). An ActiveX control property is classified as a design-time or run-time property depending on when you can change it. A design-time property can be changed using the Properties Window of the AppBuilder. A run-time property can be changed from the 4GL at run time. Generally, you can read both design-time and run-time properties at run time. In all other respects, COM object properties are functionally analogous to widget attributes.
A COM object method is a specialized function associated with a COM object that performs an action on the COM object or alters the behavior of the COM object. COM object methods may or may not return a value and may or may not require parameters. A return value may be a component handle to another COM object; however, many methods return other types of information or no information at all. Like widget methods, you execute COM object methods by direct invocation as statements rather than by invocation as part of an expression. In all other respects, COM object methods are functionally analogous to widget methods.
The basic syntax for referencing COM object properties and methods from Progress is similar to widget attribute and method references. The main differences include:
- You can chain together COM object property and method references that return component handles into a single reference. Thus, you might use a property value to reference a method and a method return value to reference a property.
- You might have to specify the parameters of COM object methods with more type information, depending on the methods and how the COM objects are implemented.
- All COM objects are dynamic objects, so you never qualify a COM object reference by a static container reference (such as a static frame or menu widget).
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