R help - Aug 2006 - tcl/tk bind destroy event

Hello!

I want to create a messagebox whenever the user wants to destroy the window 
(e.g. <Alt-F4> or the 'x' in the right top corner) and ask if a
modified file
should be saved or not.

If 'cancel' is chosen then nothing should happen and the windows still
should be
existing. This doesn't work. When I press cancel the window will be
destroyed
although.

I also implemented a menu item 'Quit' where I show the same messagebox
and there
it works fine.

How can I make it work or is there another method to do this? I'm very new
to R
and tcl/tk.

Here is part of my code:


   exitProg <- function()
   {
     returnVal <- tkmessageBox(title="Question",
       message="Save modified file?",
       icon="question", type="yesnocancel",
default="yes")

     returnVal <- as.character(returnVal)

     if( returnVal == "yes" )
     {
       # save file
       value <- saveFile()
       # destroy window when save was successfull
       if( value == 1 )
         tkdestroy(mw)
     }
     if( returnVal == "no" )
     {
       tkdestroy(mw)
     }
     if( returnVal == "cancel" )
     {
       # do nothing
       cat("Cancel was pressed.\n")
     }
   }

   # bind the destroy event in order to show a message box
   tkbind(mw,"<Destroy>",exitProg)

   # menu item which works fine
   tkadd(fileMenu, "command", label="Quit",
command=exitProg)



Thank you.

Franco Mendolia

Perhaps Destroy key is unknown by Tcl; it is not in the
Event modifiers table in Welch Book...
But try with <Control-L> or <Shift-Control_L>, it runs
(but not with <Control_L-Shift> ??).

Use xmodmap to see the current mappings from keys to modifiers.

Jean Coursol

On Wed, 2 Aug 2006, Franco Mendolia wrote:
> Hello!
>
> I want to create a messagebox whenever the user wants to destroy the window
> (e.g. <Alt-F4> or the 'x' in the right top corner) and ask if
a modified file
> should be saved or not.
>
> If 'cancel' is chosen then nothing should happen and the windows
still should be
> existing. This doesn't work. When I press cancel the window will be
destroyed
> although.
>
> I also implemented a menu item 'Quit' where I show the same
messagebox and there
> it works fine.
>
> How can I make it work or is there another method to do this? I'm very
new to R
> and tcl/tk.
>
> Here is part of my code:
>
>
>    exitProg <- function()
>    {
>      returnVal <- tkmessageBox(title="Question",
>        message="Save modified file?",
>        icon="question", type="yesnocancel",
default="yes")
>
>      returnVal <- as.character(returnVal)
>
>      if( returnVal == "yes" )
>      {
>        # save file
>        value <- saveFile()
>        # destroy window when save was successfull
>        if( value == 1 )
>          tkdestroy(mw)
>      }
>      if( returnVal == "no" )
>      {
>        tkdestroy(mw)
>      }
>      if( returnVal == "cancel" )
>      {
>        # do nothing
>        cat("Cancel was pressed.\n")
>      }
>    }
>
>    # bind the destroy event in order to show a message box
>    tkbind(mw,"<Destroy>",exitProg)
>
>    # menu item which works fine
>    tkadd(fileMenu, "command", label="Quit",
command=exitProg)
>
>
>
> Thank you.
>
> Franco Mendolia
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Hi!
> Perhaps Destroy key is unknown by Tcl; it is not in the
> Event modifiers table in Welch Book...
I think the Destroy key is known, because when destroying the window with Alt-F4
or the littel x in the topcorner my function exitProg is executed.

What I actually search for is a possibility to let the window not be destroyed 
when user closes the window by Alt-F4 or the little x.

Franco Mendolia
>>    exitProg <- function()
>>    {
>>      returnVal <- tkmessageBox(title="Question",
>>        message="Save modified file?",
>>        icon="question", type="yesnocancel",
default="yes")
>>
>>      returnVal <- as.character(returnVal)
>>
>>      if( returnVal == "yes" )
>>      {
>>        # save file
>>        value <- saveFile()
>>        # destroy window when save was successfull
>>        if( value == 1 )
>>          tkdestroy(mw)
>>      }
>>      if( returnVal == "no" )
>>      {
>>        tkdestroy(mw)
>>      }
>>      if( returnVal == "cancel" )
>>      {
>>        # do nothing
>>        cat("Cancel was pressed.\n")
>>      }
>>    }
>>
>>    # bind the destroy event in order to show a message box
>>    tkbind(mw,"<Destroy>",exitProg)
>>
>>    # menu item which works fine
>>    tkadd(fileMenu, "command", label="Quit",
command=exitProg)