[Tutor] Multiple muti-selection dropdown options

[Alan Gauld]

On 23/02/17 22:25, Pooja Bhalode wrote:

> I am working on GUI where I have two dropdown menus in a Toplevel of the
> main root. 

That's not what your code shows. It shows scrolling listboxes, not
menus. But it seems like a Frame with a set of checkboxes would be
closer to what you actually want?

Anyway...

> The window shows as below:
> [image: Inline image 1]

As I keep pointing out you cannot send images to this list,
the server throws them away as potential security risks.

> Whereas the code is:
> 
> def selectexp():
> newlist = list()
> selection = lstbox.curselection()
> for i in selection:
> tempvar = lstbox.get(i)
> newlist.append(tempvar)
> 

Note that in this function you create a list, populate
it with values and then throw them all away. If you want
to keep the values you need to declare the list as a
global variable.

> for val in newlist:
> print (val)

Because you are not posting in plain text I can't
tell if those two lines are inside the previous
function or not. I'm assuming they are inside the
function? If not I'd expect a name error for newlist?

> def selectexp2():
> newlist2 = list()
> selection2 = lstbox2.curselection()
> for i in selection2:
> tempvar2 = lstbox2.get(i)
> newlist2.append(tempvar2)
> 
> for val in newlist2:
> print (val)

Same problem here, you declare newlist2 as a new
list inside the function, then when the function
exits it throws it away. If you want to access
variables after the function exits you need to
make them global (or start using classes and
objects)

> However, the issue is that when the user selects options from the first
> dropdown menu and moves on to selecting the second one, the first dropdown
> selections are lost, 

See comments above. Make the lists global.


-- 
Alan G
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