Move Multiple Items From One List Box To Other List Box/Combo Box

Preparations

Add 2 List Boxes and 1 Command Button to your form.
Set List1 MultiSelect property to 1 - Simple.

Form Code

Private Sub Command1_Click()
'if List1 is empty - exit, to avoid error
If List1.ListCount = 0 Then Exit Sub
Dim CurItem As Integer
CurItem = 0
Do
'if the item is selected
If List1.Selected(CurItem) Then
'add it to the second List Box. If you want to add it to Combo Box,
'change the "List2" below with your combo Box name
'for example: Combo1.AddItem List1.List(CurItem)
List2.AddItem List1.List(CurItem)
'and delete it from List1 List Box
List1.RemoveItem (CurItem)
Else
CurItem = CurItem + 1
End If
Loop Until CurItem = List1.ListCount
End Sub
Private Sub Form_Load()
'add few items to the List Box
For i = 1 To 10
List1.AddItem "Item " & i
Next
End Sub