Chapter 14: Creating a User Interface Panel 319
iTool Developer’s Guide Creating Callback Routines
For example, if you have saved a state structure containing widget information in the
user value of the first child widget of the panel widget, code similar to the following
would allow you to retrieve that state structure:
; Make sure we have a valid widget ID.
IF ~ WIDGET_INFO(wPanel, /VALID) THEN RETURN
; Retrieve the widget ID of the first child widget of
; the UI panel.
wChild = WIDGET_INFO(wPanel, /CHILD)
; Retrieve the state structure from the user value of
; the first child widget.
WIDGET_CONTROL, wChild, GET_UVALUE = state
This technique is used in the example user interface panel described in “Example: A
Simple UI Panel” on page 322.
