AutoCAD VB :: All Layers Locked Except Active Layer Chosen In Combobox?

I have a form with a combobox and a commandbutton.

 All layers in the layermanager must be locked except the active layer chosen in the combobox. I try it with this code but it’s not the right solution.

Private Sub CommandButton1_Click()Dim layer As AcadLayer'check if all layers are lockedIf layer.Lock = False Thenlayer.Lock = True'make the layer selected in the combobox currentThisDrawing.ActiveLayer = ThisDrawing.Layers.Item(ComboBox1.Text)End SubPrivate Sub UserForm_Initialize() Dim layerColl As AcadLayers Dim layer As AcadLayer Dim LayList As String ' all layers locked For Each layer In ThisDrawing.Layers If layer.Lock = False Then layer.Lock = True End IfNext 'fill combobox Set layerColl = ThisDrawing.Layers For Each layer In layerColl ComboBox1.AddItem layer.Name Next End Sub

 2. When I choose the for next method to lock all layers (40 layers) it’s very slow.