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{alias:qdestroyed}

Name

qdestroyed — catch widget destruction

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Deleting a widget is not the same as closing it. Closing in itself just renders the widget invisible, while still retaining the widget in the computers memory for later redisplay. Deleting a widget removes the widget entirely from memory, requiring that the widget be re-created in order to be redisplayed. A widget is always closed before it is deleted.

Arguments

widget

The widget for which we want to catch the destruction event. This can be any widget or qaction .

cmds

Tcl statements to be executed when the widget is destructed. This will often be the name of a Tcl procedure. The widget's children are destroyed immediately after these commands are processed.

Examples

Ex.1: Catching a destruct event

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#
# Procedure to be called when the widget is destructing.
#

proc killed {} {
  puts "Object destroyed"
}

set w [qwidget]

# This is needed for the widget to be deleted when closing
qsetattribute $w deleteonclose

# Assign the 'killed' procedure as destruction-callback
qdestroyed $w killed

qshow $w

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