Delphi in a Nutshell

Name

Stored Directive

Syntax

property Name: Type Directives... stored Boolean;

Description

The stored directive takes a Boolean value: a method that returns a Boolean result, a Boolean-type field reference, or a constant expression of Boolean type. The property’s RTTI records the field offset, method reference, or constant value, and Delphi’s IDE uses this information to decide whether to omit the property from the .dfm file.

The IDE calls the method, checks the field’s value, or uses the constant Boolean value, and if the value is False, the property is not saved to the .dfm file. If the stored value is True, the default behavior occurs, namely, that the property is stored if its value is different from the default value.

Tips and Tricks

• The stored directive is often misunderstood. Setting stored to True does not force Delphi to store the property value in the .dfm file. True is the default value of the stored directive. Instead, all you can do is omit the property from the .dfm file by setting stored to False.

• You can use stored with properties at any access level, but it has meaning only for published properties.

• If you use a method name, the method can be static or virtual, but not dynamic or a message handler.

• A field reference can be a field name, a record member, or an array element with a constant index. The field reference must have a Boolean type.

Example

Delphi’s TFont class lets you specify a font’s size in points or pixels. The Height property is the font’s height in pixels, ...