How to remove listbox items in sync with another listbox

General
1

I have two listboxes that I need to modify together. It is broadly working, but there is a problem when it comes to removing items. I’m using code similar to the code below. Adding and editing items in listbox A results in the same items changing in listbox B. However, when I remove a listbox item from listbox A, I find that all but one of the matching listbox items are removed from listbox B. For example, if the item “One” appears once in listbox A and three times in listbox B, removing “One” in listbox A results in two of the three disappearing from listbox B. The last one remains in the list.

I think this might be because I am doing

for i as integer = 0 to listboxB.RowCount - 1
[…]
listboxB.removeRowAt(i)

and each time round the loop the RowCount is reducing by 1, so things may be getting out of sync.

I’m not sure what to do about this. Should I do the loop with a reducing counter, or is there something else I could do?

Here is the current code.

for i as integer = 0 to listB.RowCount - 1
  if listB.CellTextAt(i, 0) = tmpChoiceText then
    // Remove this row
    listB.RemoveRowAt(i)
    msgbox("Removed " + tmpChoiceText + " from position " + i.ToString + " in listA and listB")
  end if 
next

Any help appreciated.

Ian.

2

Reverse you’re for loop. After you have removed the first item the numbers of all the higher elements reduce by one. So the loop misses one

for i as integer = listB.LastRowIndex DownTo 0
  if listB.CellTextAt(i, 0) = tmpChoiceText then
    // Remove this row
    listB.RemoveRowAt(i)
    msgbox("Removed " + tmpChoiceText + " from position " + i.ToString + " in listA and listB")
  end if 
next

Always remove elements from the highest first.

Also Ian

1 Like
3

Perfect. Thank you.