1private void treeViewProcess_AfterCheck(object sender, TreeViewEventArgs e)
2        {
3            if (e.Node.Level == 0)
4            {
5                e.Node.TreeView.AfterCheck -= treeViewProcess_AfterCheck;
6                foreach (TreeNode subnode in e.Node.Nodes)
7                {
8                    subnode.Checked = e.Node.Checked;
9                }
10                e.Node.TreeView.AfterCheck += new TreeViewEventHandler(treeViewProcess_AfterCheck);
11            }
12            else if (e.Node.Level == 1)
13            {
14                bool check = true;
15                int i = 0;
16                while (i<e.Node.Parent.Nodes.Count && check)
17                {
18                    check = check && e.Node.Parent.Nodes[i].Checked;
19                    i++;
20                }
21                e.Node.TreeView.AfterCheck -= treeViewProcess_AfterCheck;
22                e.Node.Parent.Checked = check;
23                e.Node.TreeView.AfterCheck += new TreeViewEventHandler(treeViewProcess_AfterCheck);
24            }
25        }