向treeview中加载数据

1、获取树节点的值，用事件AfterSelect加载（id值的获取，用name来获取）

2、双击treeview控件得到

private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
        {
            string sql = "select * from emp";
            if (e.Node.Level > 0)//Level控件中树视图的深度
                sql = "select * from emp where dept_id=" + e.Node.Tag;//
            DataTable dt = DbAccess.MySqlHelper.getDataTable(sql);
            this.dataGridView1.DataSource = dt;
        }