| Re: Using multiple top level bases created with GUIBuilder [message #34556] |
Mon, 24 March 2003 15:56  |
MKatz843
Messages: 98
Registered: March 2002
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Member |
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There are a number of ways to do this.
One way is to create a place for each of your top level bases to store
the ID of the other top-level base. That said, you have several
options.
Imagine that you create both of the top-level bases from a single
procedure. Within that procedure the two base IDs are known.
Method 1) Use pointers.
base_A_ID_ptr = ptr_new(0L) ;---- store a long integer.
base_B_ID_ptr = ptr_new(0L) ;---- store a long integer.
Now modify each of your top-level-base creation programs to accept
a new keyword that will be this pointer. When you create base A, you
don't yet know what base B's ID will be, but you can give base_A
the pointer to where that ID will be stored.
base_A_ID = create_base_A(something, something,
base_B_ID_ptr=base_B_ID_ptr)
base_B_ID = create_base_B(something, something,
base_B_ID_ptr=base_A_ID_ptr)
At this point, the pointers are empty. Now, by setting the pointers,
we give bases A and B knowledge of the other's ID.
*base_A_ID_ptr = base_A_ID
*base_B_ID_ptr = base_B_ID
The only caveat, is that you have to store the pointer-to-the-ID
somewhere within each base so that it's accessible from within the
event handler routine. It's convenient to store that information in a
UVALUE of the buttons you're clicking or some easy to get to base or
another, and then retrieve it with a widget_control, ID,
GET_UVALUE=base_ID_pointer.
Method 2) Use SET_VALUE
Another way to pass information into an existing widget is with
SET_VALUE. You have to again create a place to store the ID once you
know it, and you have to make a SET_VALUE routine for the widget. When
the base receives a SET_VALUE widget_control command, it takes the
value and stores it somewhere where it can be retrieved by the event
handler routine.
So you would do something like
base_A_ID = create_base_A(something, something)
base_B_ID = create_base_B(something, something)
widget_control, base_A_ID, SET_VALUE=base_B_ID
widget_control, base_B_ID, SET_VALUE=base_A_ID
Method 3) If widget A needs to know the ID of B but not the other way
around, then you can create B first, then give A a keyword containing
base B's ID.
base_B_ID = create_base_B(something, something)
base_A_ID = create_base_A(something, something, base_B_ID=base_B_ID)
Within base A you'll again have to find a place to store the ID for
use during the event handler. Another place to store it is in the
UVALUE of the buttons.
button = widget_button(somebase, VALUE='Show', $
UVALUE={name:'Show', ID:base_B_ID} )
Here the UVALUE is a structure and the ID of the other base is stored
in one of the structure fields.
Method 4) Use Objects
This is very similar to the pointer method, above. You create an
object or objects that will contain the IDs. Pass them to the bases
upon creation, then set the object's values properly.
Disclaimer: While objects are certainly the most elegant way to solve
this (or most any) problem, they usually do require a bit more code,
and familiarity with object programming in IDL (which is great).
Failure to mention that there exists an object-oriented solution to
such a question could provoke a kind-hearted, verbal tongue lashing
from the list gurus.
I hope one of these ways will help. Any way you slice it, I think
you'll have to make some modifications to the pre-fab code generated
by the gui builder.
Best of luck,
M. Katz
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