managing multi-listboxes

There have been several folks struggling with how to manage a dual listbox style application where items from a master list are moved to a destination list. I wrote some code to do that many years ago. This is an updated version with comments. I am hoping folks can follow along. When running the program looks like this:

[[image:multi-listbox.jpg]]

----

Here is the code:code (while I hate to admit that I make mistakes, this did have an error handling the no item selected to delete condition - it is now fixed):

[[code format="qbasic"]]
'Friuty List - an example of how to manage a listbox as a destination list building
'  the list from a master listbox.  This would work with comboboxes also.
'by Brad Moore - placed into the Public Domain Jan 2006

nomainwin

'this is how many entries the destination list box can hold
maxEntries = 100

'create the arrays
dimDIM arrayOne$(12)
dim
DIM arrayTwo$(maxEntries)

'this is the master data - you can do this with read/data statements also,
'  wondering how this works? - check out the WORD$ function in the helpfile.
a$ = "Apples Bananas Cherries Figs Grapefriut Honeydew Kiwi Lime Mango Nectarine Papaya Pear"
forFOR x = 1 toTO 12 : arrayOne$(x) = word$(a$,x) : nextNEXT x

'initialize our counter for items in the destination listbox
idx = 0

'setup the window and controls
WindowWidth = 280
WindowHeight = 260
UpperLeftX = int((DisplayWidth/2)-(WindowWidth/2))INT((DisplayWidth/2)-(WindowWidth/2))
UpperLeftY = int((DisplayHeight/2)-(WindowHeight/2))

listbox #main.lbx1,arrayOne$(),wait,10,10,100,170INT((DisplayHeight/2)-(WindowHeight/2))
listbox #main.lbx2,arrayTwo$(),wait,158,10,100,170#main.lbx1,arrayOne$(),WAIT,10,10,100,170
listbox #main.lbx2,arrayTwo$(),WAIT,158,10,100,170
button #main.moveBtn,">",[move],UL,114,30,40,30
button #main.deleteBtn,"Delete",[delete],UL,114,62,40,30
button #main.deleteBtn,"Sort",[sort],UL,114,94,40,30
button #main.closeBtn, "Close",[quit],UL,158,189,100,30
button #main.inspectBtn, "Inspect Array",[inspect],UL,52,189,100,30

'open the window
openOPEN "Friuty List" forFOR dialog asAS #main
print
PRINT #main,"trapclose [quit]"
print
PRINT #main.lbx1,"selectindex 1"
wait

WAIT
[move]
'get the index value for the item in the master list
printPRINT #main.lbx1,"selectionindex? i"
'make sure there is room to add another item
ifIF idx = maxEntries thenTHEN
    notice "The destination list already contains the maximum number of entries"
    wait
end ifWAIT
END IF
'increment the index and add the item
idx = idx + 1
arrayTwo$(idx) = arrayOne$(i)
'reload causes the listbox view to be refreshed so our item shows up
printPRINT #main.lbx2,"reload"
wait

WAIT
[delete]
'get the index value for the item in the destination list
printPRINT #main.lbx2,"selectionindex? i"
if i = 0 then
    'turns out the user has not selected anything to delete
    notice "You must select an item from the destination list to delete " + _
           "before a delete can be preformed."
    wait
end if
'if this is not the last item we need to shift the array up to fill the gap
ifIF i < idx then
   forTHEN
   FOR x = i toTO idx - 1
      arrayTwo$(x) = arrayTwo$(x+1)
   nextNEXT x
end if
END IF
'set the last item to a null string
arrayTwo$(idx) = ""
'decrement the total number of items in the destination array
idx = idx - 1
'reload causes the listbox view to be refreshed so our item shows up
printPRINT #main.lbx2,"reload"
wait

WAIT

[inspect]
'inspect opens a new window in dialog modal form - set up that window
WindowWidth = 372
WindowHeight = 470
UpperLeftX = INT((DisplayWidth-(2 * WindowWidth))/2)
UpperLeftY = INT((DisplayHeight-(2 * WindowHeight))/2)
button  #inspect.closeBtn, "Close", [closeMe], UL, 225, 395, 125, 30
texteditor  #inspect.tedit, 9, 13, 340, 375
'open the window
OpenOPEN "Array Inspector" forFOR Dialog_modal asAS #inspect
#inspect "trapclose [closeMe]"
#inspect "font ms_sans_serif 10"

'initialize the output string
ifIF idx = 0 then
    out$THEN
    OUT$ = "There are no items in the destination array."
else
    out$
ELSE
    OUT$ = "There are " + str$(idx)STR$(idx) + " items in the destination array." + chr$(10)
end if
CHR$(10)
END IF
'add the array items to the output string.  Note the right$ trick which pads index with leading zeros
forFOR x = 1 toTO idx
    out$
    OUT$ = out$OUT$ + "Item " + right$("000"RIGHT$("000" + str$(x),3)STR$(x),3) + " = " + arrayTwo$(x) + chr$(10)
nextCHR$(10)
NEXT x
'dump the output string to the texteditor
#inspect.tedit out$
Wait
OUT$
WAIT
[closeMe]
closeCLOSE #inspect
wait

WAIT

[sort]
'if there is more than one item in the destination array call the sort function to sort it
ifIF idx > 1 thenTHEN sort arrayTwo$(), 1, idx
'reload causes the listbox view to be refreshed so our item shows up
printPRINT #main.lbx2,"reload"
wait
WAIT
[quit]
CLOSE #main
END

[quit]
close #main
end
[[code]]

[[user:bradmoore|1138127448]]