Name: deleteField

Type: message

Syntax: deleteField

Summary: Sent to a <field> just before it is removed from the <stack>.

Associations: field

Introduced: 1.0

OS: mac,windows,linux,ios,android

Platforms: desktop,server,web,mobile

Example:
on deleteField -- first save the contents in a custom property
  set the (the short name of the target) of this card to target
  pass deleteField
end deleteField

Description:
Handle the <deleteField> <message> if you want to perform cleanup before a <field> is removed from the <stack>.

The actual deletion is not triggered by the <deleteField> <message>, so <trap|trapping> the <message> and not allowing it to <pass> does not prevent the <field> from being removed.

However, the undo <command> will restore a <field> after it is deleted by the user. For example, the following <handler>, placed in a <card> or stack <script>, effectively prevents a <field> from being deleted by the user:

  on deleteField
    beep
    send "undo" to this card in 5 milliseconds
  end deleteField

References: field (keyword), script (property), delete (command), stack (object), handler (glossary), trap (glossary), message (glossary), command (glossary), card (glossary), pass (control_st)

Tags: objects
