Private Sub UserForm_Initialize()
    Dim vaItems As Variant
    Dim i As Long, j As Long
    Dim vTemp As Variant
    
    Me.ListBox1.AddItem "B"
    Me.ListBox1.AddItem "A"
    Me.ListBox1.AddItem "D"
    Me.ListBox1.AddItem "C"
    
    'Put the items in a variant array
    vaItems = Me.ListBox1.List
    
    'Steal code from John Walkenbach’s Excel Power Programming
    'with VBA to sort the array
    For i = LBound(vaItems, 1) To UBound(vaItems, 1) - 1
        For j = i + 1 To UBound(vaItems, 1)
            If vaItems(i, 0) > vaItems(j, 0) Then
                vTemp = vaItems(i, 0)
                vaItems(i, 0) = vaItems(j, 0)
                vaItems(j, 0) = vTemp
            End If
        Next j
    Next i
    
    'Clear the listbox
    Me.ListBox1.Clear
    
    'Add the sorted array back to the listbox
    For i = LBound(vaItems, 1) To UBound(vaItems, 1)
        Me.ListBox1.AddItem vaItems(i, 0)
    Next i
End Sub