http://www.cnblogs.com/xiachufeng/archive/2009/12/29/1635538.html
TreeNode node = new TreeNode();
node.Text = "上海";
node.Value = "上海";
this.TreeView2.Nodes.Add(node);
TreeNode node1 = new TreeNode();
node1.Text = "浦东";
node1.Value = "浦东";
node.ChildNodes.Add(node1);
TreeNode DongGouNode = new TreeNode();
DongGouNode.Text = "东沟";
DongGouNode.Value = "东沟";
node1.ChildNodes.Add(DongGouNode);
TreeNode node2 = new TreeNode();
node2.Text = "嘉定";
node2.Value = "嘉定";
node.ChildNodes.Add(node2);
TreeNode BeiJingNode = new TreeNode();
BeiJingNode.Text = "北京";
BeiJingNode.Value = "beijing";
this.TreeView2.Nodes.Add(BeiJingNode);