TDocument and TView each have some general properties.

These properties are available in any classes derived from TDocument and TView. These properties are indexed by a list of enumerated values. The first property for every TDocument- and TView-derived class should be PrevProperty. The last value in the property list should be NextProperty. These two values delimit the property list of every document and view object. They ensure that your property list starts at the correct value and does not overstep another property's value, and they allow derived classes to ensure that their property lists start at a suitable value. PrevProperty should be set to the value of the most direct base class's NextProperty - 1.

For example, a property list for a class derived from TDocument might look something like this:

enum {
 PrevProperty = TDocument::NextProperty-1,
 Size,
 StorageSize,
 NextProperty,
};

Note: Use the scope operator (::) when setting PrevProperty to ensure that you set it to the correct value for NextProperty.

Property names are usually contained in an array of strings, with the position of each name in the array corresponding to its enumerated property index. However, when adding properties to a derived class, you can store and access the strings in any style you want. Because you have to write the functions to access the properties, complicated storage schemes aren't recommended. A property name should be a simple description of the property.

Property attributes, like pfGetText, are likewise usually contained in an array (of int). You can set up the array any way you like, but the usual practice is to have the attributes for a property contained in an array corresponding to the value of its property index.

See Also