Release 10.1A: OpenEdge Development:
Progress Dynamics Advanced Development

Miscellaneous link properties

This section describes some useful link properties.

SupportedLinks

This CHARACTER property holds the list of all links routinely created for an object. It is a comma-separated list of link names, including the –Source or –Target suffix. As described earlier, you need a <link>Source or <link>Target property to hold the handles of the objects that use the link, along with a <link>SourceEvents or <link>TargetEvents property to hold the list of the events that the object should subscribe to in the related object.

This property is initialized in the property include files for the various SmartObjects. Because of the dependencies on other property names, you should not modify it. The user link mechanism allows you to create additional links dynamically when you need them.

<link>Source and <link>Target

For each link in an object’s SupportedLinks list that is a <link>–Source, there must be a <link>Target property for the object. This holds the handle of the target for the link at run time. If the object can have multiple targets for the link, then the data type of the property must be CHARACTER, to hold the list of object handles. If the object can have only one target for the link, then the data type of the property should be HANDLE, to hold that one procedure handle in native form. Likewise, for each link in an object’s SupportedLinks list that is a <link>–Target, there must be a <link>Source property for the object, which holds the handle of the source at run time. The same data type rules apply.

<link>SourceEvents and <link>TargetEvents

As described earlier in this section, these properties store the list of events that the object should be subscribed to in the handle of the object at the other end of the link. The constructObject procedure uses these properties together to accomplish all of the linking of objects, using the 4GL PUBLISH and SUBSCRIBE statements.

InactiveLinks

This CHARACTER property contains a list of all links and handles for an object that are currently inactive.