You can add a property to a user-defined class at any time.
When you have defined a property, it can be accessed for any instance of the class in which it is defined or for any instance of a subclass of that class. (See also "Promoting a Local Variable to be a Property on the Current Class", earlier in this chapter.)
Attribute properties are primitive types such as strings or collections of primitive types (for example, a string array) that are characteristics (or features) of an object. Attributes do not possess identity but the objects to which they apply determine their individuality.
Reference properties contain references to other objects; that is, they are end points in one- or two-directional relationships.
Properties cannot be added to, changed, or removed from system classes. Adding, changing, or deleting a property may cause the class to be marked for reorganization if instances of that class already exist. (A class is not normally marked for reorganization when you add a reference that is an exclusive collection.)
For details about defining references to ActiveX automation events, see "
For details about renaming a property selected within the body of a method in the editor pane, see "Renaming or Changing an Entity", later in this chapter.
For details about dynamic design-time and runtime properties, see "Dynamic Clusters and Properties", later in this chapter. For details about the scope of design-time dynamic properties, including a table providing usage decisions, see "Design-Time Dynamic Property Scope and Notes", later in this chapter. See also "