void UnsetCheckStates (TreeNodeCollection col, NameValueCollection states)
{
foreach (TreeNode node in col) {
if (node.ShowCheckBoxInternal && node.Checked) {
if (states == null || states [ClientID + "_cs_" + node.Path] == null)
node.Checked = false;
}
if (node.HasChildData)
UnsetCheckStates (node.ChildNodes, states);
}
}