Compare listbox items

Okay what I am trying to do is compare the listbox items for additional items.

Example:

List 1 has the following items on it:

Test

Test2

Test3

Exampe

And List2 has the following items on it:

Test2

Test4

Test5

Test6

If list2 matches list1 then drop that item, however if it does not match then add the item to a list3 box. This means, if list1 has the same items as list2 then remove all the same items, and add the non same ideas from list2 to list3 making the additional items from list2 show up on list3.

Quote:

---

If list2 matches list1 then drop that item, however if it does not match then add the item to a list3 box.

---

Hope this helps...

Code:

---

Dim BoolAdd As Boolean, i As Long, j As Long
Private Sub Command1_Click()
    '~~> Set initial Flag
    BoolAdd = True
    '~~> If list2 is empty then abort operation
    If List2.ListCount = 0 Then
        MsgBox "Nothing to compare"
        Exit Sub
    '~~> if list1 is empty then copy entire list2 to list3
    ElseIf List1.ListCount = 0 Then
        For i = 0 To List2.ListCount
            List3.AddItem List2.List(i)
        Next i
    Else
        For i = List2.ListCount - 1 To 0 Step -1
            For j = 0 To List1.ListCount
                If List2.List(i) = List1.List(j) Then
                    '~~> If match found then abort
                    BoolAdd = False
                    Exit For
                End If
                DoEvents
            Next j
            '~~> If not found then add to list3
            If BoolAdd = True Then List3.AddItem List2.List(i)
            DoEvents
        Next i
    End If
End Sub

Private Sub Form_Load()
    '~~> Sample Data
   
    '~~> Adding item to list1
    List1.AddItem "Test"
    List1.AddItem "Test2"
    List1.AddItem "Test3"
   
    '~~> Adding item to list2
    List2.AddItem "Test2"
    List2.AddItem "Test4"
    List2.AddItem "Test5"
    List2.AddItem "Test6"
End Sub

---

Depending on how many items your listbox has, you may want to adapt koolsid's example using APIs vs looping thru both listboxes. Faux code looks a little like this & API search is tons faster:

Code:

---

For I = Listbox2.ListCount -1 to Step -1 ' work from bottom up
    If SendMessage(ListBox1.hWnd, LB_FINDSTRINGEXACT, -1, ByVal ListBox2.List(I)) = -1 Then
        ' not found
        ... ListBox3.Add Item ListBox2.List(I), 0
    Else ' found, remove it from #2
        ... ListBox2.RemoveItem I
    End If
Next

---

nice one keith :thumb: