ListBox without duplicates

Question

I have two ListBoxes on a UserForm. The first ListBox is linked to a table. The goal is after double clicking an item, the value is inserted in the second ListBox.

I tried to prevent duplicates from appearing in the second ListBox, so you couldn't accidentally insert the same item twice.

Private Sub listbox_variante_DblClick(ByVal Cancel As MSForms.ReturnBoolean)

Dim x As Integer

For x = 0 To listbox_variante.ListCount - 1
    If listbox_variante.Selected(x) = True Then
        listbox_seleccion.AddItem (listbox_variante.List(x))
    End If
Next x

End Sub


Private Sub UserForm_Initialize()
listbox_variante.RowSource = "Tabla2[DESCRIPCIÓN]"
End Sub

How can I prevent duplicate items being added from Listbox_variante to Listbox_seleccion?

Answer 1

I haven't tested it, but try...

Private Sub listbox_variante_DblClick(ByVal Cancel As MSForms.ReturnBoolean)

    Dim x As Long
    Dim y As Long
    Dim bFound As Boolean
    
    bFound = False
    For x = 0 To listbox_variante.ListCount - 1
        If listbox_variante.Selected(x) = True Then
            For y = 0 To listbox_seleccion.ListCount - 1
                If listbox_seleccion.List(y) = listbox_variante.List(x) Then
                    Beep 'optional
                    bFound = True
                    Exit For
                End If
            Next y
            If Not bFound Then
                listbox_seleccion.AddItem listbox_variante.List(x)
            Else
                bFound = False
            End If
        End If
    Next x

End Sub