vlr-object-reactor (AutoLISP/ActiveX)

Constructs a drawing object reactor object

Supported Platforms: Windows only

Signature

(vlr-object-reactor owners data callbacks)
owners

Type: List

An AutoLISP list of VLA-objects identifying the drawing objects to be watched.

data

Type: Integer, Real, String, List, VLA-object, Safearray, Variant, T, or nil

Any AutoLISP data to be associated with the reactor object; otherwise nil if no data.

callbacks

Type: List

A list of pairs of the following form:

(event-name . callback_function)

  • event-name is one of the following Object Events:

    Object events

    Name

    Event

    :vlr-cancelled

    The modification of the object has been canceled.

    :vlr-copied

    The object has been copied.

    :vlr-erased

    Erase-flag of the object has been set.

    :vlr-unerased

    Erase-flag of the object has been reset.

    :vlr-goodbye

    The object is about to be deleted from memory.

    :vlr-openedForModify

    The object is about to be modified.

    :vlr-modified

    The object has been modified. If the modification was canceled, also :vlr-cancelled and :vlr-modifyUndone will be fired.

    :vlr-subObjModified

    A sub-entity of the object has been modified. This event is triggered for modifications to vertices of polylines or meshes, and for attributes owned by block references.

    :vlr-modifyUndone

    The object's modification was undone.

    :vlr-modifiedXData

    The object's extended entity data has been modified.

    :vlr-unappended

    The object has been detached from the drawing database.

    :vlr-reappended

    The object has been re-attached to the drawing database.

    :vlr-objectClosed

    The object's modification has been finished.

  • callback_function is a symbol representing a function to be called when the event fires. Each callback function accepts three arguments:

    owner -- The owner of the VLA-object the event applies to.

    reactor_object -- The VLR object that called the callback function.

    list -- A list of extra data elements associated with the particular event. The contents of this list for particular events are shown in the “Object Events Callback Data” table.

    Object events callback data

    Name

    List length

    Parameters

    :vlr-cancelled

    :vlr-erased,

    :vlr-unerased

    :vlr-goodbye

    :vlr-openedForModify

    :vlr-modified

    :vlr-modifyUndone

    :vlr-modifiedXData

    :vlr-unappended

    :vlr-reappended

    :vlr-objectClosed

    0

    :vlr-copied

    1

    The object created by the copy operation (ename).

    :vlr-subObjModified

    1

    The sub-object (ename) that has been modified

Return Values

Type: VLR object

The reactor_object argument from the callback_function.

Remarks

The reactor object is added to the drawing database, but does not become persistent.

Examples

The following code attaches an object reactor to the myCircle object. It defines the reactor to respond whenever the object is modified (:vlr-modified) and to call the print-radius function in response to the modification event: 

(setq circleReactor (vlr-object-reactor (list myCircle)
         "Circle Reactor" '((:vlr-modified . print-radius))))

Related Concepts