check all or none items in checkedlistbox

if (clientList.CheckedItems.Count == 0)
for (int i = 0; i < clientList.Items.Count; i++)
{
clientList.SetItemChecked(i, true);
}
else
for (int i = 0; i < clientList.Items.Count; i++)
{
clientList.SetItemChecked(i, false);
}