 
 subsection3_3_5.html  subsection3_3_4.html  subsubsection3_3_4_3.html  tableofcontents3_1.html   Next: subsection3_3_5.html The TixSelect Widget Up: subsection3_3_4.html Another Tix Widget:  Previous: subsubsection3_3_4_3.html Static Options    Monitoring the User's Browsing Actions  
When the user drags the mouse pointer over the listbox, the listbox
  item under the pointer will be highlighted and a ``browse event''
  will be generated. If you want to keep track of what items the user
  has browses through, you can use the 
-browsecmd option. Here
  is an example:
     tixComboBox .c -browsecmd mybrowse    ....
    proc mybrowse {item} {
        puts "user has browsed $item"
    }
When the Tcl command specified by the 
-browsecmd option is
  called, it will be called with one parameter: the current item that
  the user has highlighted.
The 
-browsecmd is useful because it gives the user the
  possibility of temporarily seeing the results of several choices
  before committing to a final choice.
For example, we can list a set of image files in a ComboBox. When
  the user single-clicks on an item on the ComboBox, we want to show a
  simplified view of that image. After the user has browsed through
  several images, he can finally decide on which image he wants by
  double-clicking on that item in the listbox.
The following is some pseudo Tcl code that does this. Please notice
  that the 
-browsecmd procedure is called every time the user
  single-clicks on an item or drags the mouse pointer in the listbox.
  The 
-command procedure is only called when the user
  double-clicks on an item.
 tixComboBox .c -dropdown false -browsecmd show_simple -command load_fullsize .c insert end "/pkg/images/flowers.gif"
.c insert end "/pkg/images/jimmy.gif"
.c insert end "/pkg/images/ncsa.gif"
proc show_simple {filename} {
    # Load in a simplified version of $filename
}
proc load_fullsize {filename} {
    # Load in the full size image in $filename
}
As we shall see, all Tix widgets that let us do some sort of
  selections have the 
-browsecmd option. The -browsecmd  option allows us to respond to user events in a simple,
  straight-forward manner. Of course, you can do the same thing with
  the Tk 
bind command, but you don't want to do that unless you
  are very fond of things like 
$<$Control-Shift-ButtonRelease-1$>$  and 
"%x%X$w%W%w".
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