TCustomVariantType¶

Base class for a custom variant type.

Declaration¶

Source position: variants.pp line 168

type

  TCustomVariantType = class(TObject, IInterface)
  public
    constructor Create; overload;
    constructor Create(RequestedVarType: tvartype); overload;
    destructor Destroy;
    function IsClear : Boolean;
    procedure Cast;
    procedure CastTo;
    procedure CastToOle;
    procedure Clear;
    procedure Copy;
    procedure BinaryOp;
    procedure UnaryOp;
    function CompareOp : Boolean;
    procedure Compare;
    property VarType: tvartype; {r}
  end;

Inheritance¶

Implements: IInterface

Description¶

TCustomVariantType is used as a base class to implement custom variants. To define a custom variant type, a descendent of TCustomVariant must be made, and the appropriate methods must be overridden and implemented according to the specifications of the new type. Typically this means defining how your new type maps to another variant or a basic type.

Note that the TCustomVariantType descendent does not hold the data of the variant: it just describes how a variant record (TVarRec) that contains the new type's data can be examined or manipulated.

Properties¶

Member	Visibility	Description
VarType read only	public	Registered type.

See all Properties

Methods¶

Member	Visibility	Description
BinaryOp	public	Perform a binary mathematical operation.
Cast	public	Cast a custom variant to another type.
CastTo	public	Cast a custom variant to another type.
CastToOle	public	Cast variant value to OLE value.
Clear	public	Clear a value.
Compare	public	Comparison 2 custom variant values.
CompareOp	public	Check result of a comparison between 2 custom variant values.
Copy	public	Copy a custom variant value.
Create	public	Instantiate a new custom variant type.
Destroy	public	Unregister variant type.
IsClear	public	Is the custom value unassigned ?
UnaryOp	public	Perform a unary mathematical operation.

See all Methods