Version 3 of Adding 'history' to BWidget ComboBox widgets.

WJG (10th June, 2005) Why doesn't the BWidget ComboBox does have a 'built-in' means of updating the selection list from data validated in its entry box. Perhaps, it has and I haven't looked hard enough. Anyway, it was quicker to just cook something up. So here's my offering.

 # -------------------------------------------------------------
 # ComboBox_history.tcl
 # Written by William J Giddings, 2005
 # -------------------------------------------------------------
 # 
 # Purpose:
 # --------
 # To provide history for the BWidget ComboBox. 
 # 
 # Note:
 # -----
 # * This is not achieved by manipulating the BWidet code but by 
 # simply providing a suitable proceedure to be called when the 
 # entry subwidget is validated.
 # * New vallidated entries are placed at the top of the list.
 # * Duplicate entries will not be added.
 #
 # Use:
 # ---------------
 # ComboBox .cmb -values {A B C} -command _h
 #
 # -------------------------------------------------------------

 # -------------------------------------------------------------
 # a simple handler, no args required
 # -------------------------------------------------------------

 proc _h {} {  
    set w [winfo parent [focus]] 
    set a [$w get]
    set b [$w cget -values]
    #check to see if value already there..
    if { [lsearch -exact $b $a] } { $w configure -values "$a $b"} 
 }

 # -------------------------------------------------------------
 # the uniquitous demo!
 # -------------------------------------------------------------
 proc demo {} {
    package require BWidget
    pack [ComboBox .cmb -values {A B C} -command _h]
 }

 demo