Sub chkCheckAllItems_CheckedChange(Checked As Boolean)
For i= 0 To clv3.GetSize -1 'CustomListView dimmed as clv3
Dim pnl As Panel
pnl = clv3.GetPanel(i)
Dim chk As CheckBox
chk= pnl.GetView(2) 'presuming checkbox is 3rd view in panel (same as example)
chk.Checked = True
Next
End Sub