| Re: Dynamically adding and removing widgets [message #46450] |
Wed, 23 November 2005 23:16 |
peter.albert@gmx.de
Messages: 108
Registered: July 2005
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Senior Member |
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Hi all,
well, I'd guess that the state variable *does* exist in the routine
"show_phenomenon":
In "pro event_handler", state is assigned to the uvalue of the parent
widget :
WIDGET_CONTROL,Event.TOP,SET_UVALUE=state,/NO_COPY
It is correct that the variable "state" itself is undefined afterwards,
but it does still exist as the UVALUE or the root widget. Then the
routine "show_phenomenon" is called with the "event" variable as a
parameter, which is fine, as "event" also still exists. Especially,
event.top still points at the parent widget. Therefore, when calling
widget_control,Event.Top,GET_UVALUE=state
within "show_phenomenon", everything works as expected and the "state"
is read from the parent widget's uvalue.
So where is the problem coming from?
The real problem is with the "base" variable:
You use
mask_disp = WIDGET_DRAW(base,xsize=numCols,ysize=numRows)
where "base" is expected to be a valid widget ID. As you showed
yourself, however, "base" holds the string "mask_tab":
>> IDL> print, base
>> mask_tab
Why?
Because in the line above you use
base = widget_info(state.mask_tab,/UNAME)
Using /UNAME with WIDGET_INFO returns the user name of the widget.
So probably
mask_disp = WIDGET_DRAW(state.mask_tab, xsize=numCols,ysize=numRows)
is just what you want?
It will create the new draw widget right in the widget whose ID is
state.mask_tab.
Cheers,
Peter
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| Re: Dynamically adding and removing widgets [message #46461 is a reply to message #46450] |
Wed, 23 November 2005 11:23  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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akkiraju writes:
> Thanks. I have cross checked my sate variable value in the
> "show_phenomenon" procedure.
> IDL> print, base
> mask_tab
> IDL> print,state
> { 7 8 6 20 21
> 16 17 18}
>
> state is not undefined in my case, I can access the components and
> their names from the show_phenomenon procedure. But when I use these
> names to add new widgets it doesnt work, thats the real problem.
I agree with Antonio. When you get into Show_Phenomenon and look
for your state variable in the UValue of the top-level base it is
not defined. It can't be.
I'm not sure how you think you are checking it, but I am
100% sure that what you did is not what is happening in
your program. I would stop the program just before the
Show_Phenomenon call, then step into the Show_Phenomenon
code. You will see that state is undefined there.
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
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| Re: Dynamically adding and removing widgets [message #46467 is a reply to message #46461] |
Wed, 23 November 2005 10:29 |
akkiraju
Messages: 3
Registered: November 2005
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Junior Member |
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hi Antonio,
Thanks. I have cross checked my sate variable value in the
"show_phenomenon" procedure.
IDL> print, base
mask_tab
IDL> print,state
{ 7 8 6 20 21
16 17 18}
state is not undefined in my case, I can access the components and
their names from the show_phenomenon procedure. But when I use these
names to add new widgets it doesnt work, thats the real problem.
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| Re: Dynamically adding and removing widgets [message #46469 is a reply to message #46467] |
Wed, 23 November 2005 09:58 |
Antonio Santiago
Messages: 201
Registered: February 2004
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Senior Member |
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> 4. One of my event handlers calls a procedure called
> show_phenomenon
>
> pro event_handler Event
> ----
> WIDGET_CONTROL,Event.TOP,SET_UVALUE=state,/NO_COPY
> show_phenomenon,.....,....,Event
> ----
> end
>
I think your problem is with the /NO_COPY keyword, this unidefines the
"state".
See PDF manual:
"However, it has the side effect of causing the source variable to
become undefined. On a “set” operation (using the SET_UVALUE keyword to
WIDGET_CONTROL), the variable passed as value becomes undefined. On a
“get”
operation (GET_UVALUE keyword to WIDGET_CONTROL), the user value of the
widget in question becomes undefined."
Then inside your "Show_phenomenon" procedure the "state" value is
undefined.
Bye :)
--
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