An attribute of GUI Object domain is an interface pointer to an object. In keeping with the object-oriented nature of OLE, an application does not have access to the entire object, just to its external interfaces. These external interfaces are called methods, properties, and events.
The object could be a standard window control such as a button, listbox, or entry field, or an embedded/linked object such as a Microsoft Excel™ spreadsheet or Word™ document.
Typically in application logic, a GUIObject attribute is used to temporarily reference various objects as required to interact with those objects. It is possible for a GUIObject to contain a reference to an object even though that object no longer exists. When application logic sets a GUIObject attribute to a new reference, any existing object referenced by that GUIObject is first released before being set to the new value. When a GUIObject attribute contains an object reference and that object still exists and has not been destroyed, the GUIObject can successfully be set to a new value without first setting the GUIObject to NOTHING. But, if that initial object no longer exists, then the release of that reference will follow an invalid pointer to a destroyed object.
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