A COM object’s interface will often define property values that control its nature. A property named X will be written and read using methods named putX (or setX) and getX, respectively. If you’ve developed ActiveX or OLE controls in Visual Basic, you’ve worked with property-setting methods such as these. No COM interface allows member values to be directly assigned or read; every access to a COM object must be through a method of some kind. The only exceptions to this rule are the constants that are exposed by some interfaces; such a constant value can be read and usually defines a set of values, such as true and false, that are returned by a method.