IDChanged

Type

message

Summary

Sent to an image when its ID property is changed.

Syntax

IDChanged <pOldID>, <pNewID>

Description

Handle the IDChanged message if you want to make updates when an image's ID is changed.

The ID property of most objects is set when the object is created and cannot be changed. There are two exceptions:stacks and images.

You can set the ID of an image to any positive integer. Be careful not to set an image ID to a number that's the ID of another image in the same stack : since LiveCode uses IDs to keep track of objects, a conflict may result in the inability to access one or both objects. The following ID numbers are reserved and should not be used for image IDs:

• 1-100: reserved for built-in cursors
• 101-135: reserved for built-in brush shapes
• 236-300: reserved for built-in patterns
• 301-1000: reserved for built-in icons
• 101,000-103,000: reserved
• 200,000-299,999: reserved for application use

The actual change is not triggered by the IDChanged message, so trapping the message and not allowing it to pass does not prevent the ID from being changed.

Parameters

Name	Type	Description
pOldID		The image's original ID number.
pNewID		The image's new ID number.

Examples

on IDChanged prevID,currentID -- update ID stored in another object
  set the storedID[the short name of image ID prevID] of this stack \
     to currentID
end IDChanged

Related

glossary: object, property, trap, message, image

keyword: image, integer

message: nameChanged

object: stack, image

property: altID, ID

control structure: pass

function: stacks

Compatibility and Support

Introduced

LiveCode 1.0

OS

mac

windows

linux

ios

android

Platforms

desktop

server

mobile