private void button2_Click(object sender, EventArgs e)

        {            

            foreach (TreeNode n in TreeView1.Nodes)

            {

                ErgodicTreeView(n);

            }

        }

void ErgodicTreeView(TreeNode tn)

        {

            if (tn == null) return;

            //查找到某节点时

            if (tn.Text.Equals("英山县"))

            {

                //遍历递归获取父节点，将父节点全部展开

                prenode(tn);

                //选中某节点，并加背景颜色

                TreeView1.SelectedNode = tn;

                TreeView1.SelectedNode.BackColor = System.Drawing.Color.Red;

            }

            foreach (TreeNode n in tn.Nodes)

            {

                ErgodicTreeView(n);

            }

        }

        void prenode(TreeNode m)

        {

            if (m.Parent.Text != null)

            {

                m.Parent.Expand();

                //当为项级节点时

                if (m.Parent.Level == )

                {

                    m.Parent.Expand();

                }

                 //不是项级节点时

                else

                {

                    prenode(m.Parent);

                }

            }

        }