Clear treeview check boxes at runtime

lets name tree view control : trvwMultiUnit

then call this function : clearTrrVwChkBox()

private void clearTrrVwChkBox()
{

foreach(TreeNode tn in trvwMultiUnit.Nodes)
{
TreeNodeCollection cNodes = tn.ChildNodes;
foreach(TreeNode cNode in cNodes )
{
if(cNode.Checked)
{
cNode.Checked = false;
}
}
}
}