Mastering Delphi Programming: A Complete Reference Guide

Delphi idioms – attributes

Before we can use an attribute, we have to declare it. To declare an attribute, we have to derive it from a special class, TCustomAttribute:

type  SpecialClassAttribute = class(TCustomAttribute)  end;

To use this attribute, we annotate a Delphi entity (for example a class) by enclosing the attribute name in square brackets:

type  [SpecialClassAttribute]  TThisIsMySpecialClass = class  end;

The Delphi compiler allows us to shorten the attribute name if it ends with Attribute:

type  [SpecialClass]  TThisIsAnotherSpecialClass = class  end;

By a commonly accepted convention, attribute names end with Attribute and don't start with a T prefix (even though they are technically classes).

A code can only use an attribute if the ...