新手跪求treeView控件链接SQL数据库树形源码！！3Q

private void BindProductNode()
{
      TreeNode root = new TreeNode("Product Phone", "Product Phone", "", "#", "");
      root.Expanded = true;
      tvAcc.Nodes.Add(root);

       DataTable dtPlat = new DataTable();
       dtPlat = reportBLL.GetPlatformList();// Data Source from db

       DataTable dtPhone = new DataTable();//sub's title data source
       for (int i = 0; i < dtPlat.Rows.Count; i++)
       {
           string platName = dtPlat.Rows[i]["Platform"].ToString();
           string accID = dtPlat.Rows[i]["Platform"].ToString();
           TreeNode tree1 = new TreeNode(platName, accID, "", "", "");
           tree1.Expanded = false;
           root.ChildNodes.Add(tree1);

           dtPhone = reportBLL.GetPhoneList(platName);//eg."eDream6", get sub title's data source.
           for (int j = 0; j < dtPhone.Rows.Count; j++)
           {
               string phone = dtPhone.Rows[j]["Product"].ToString();
               TreeNode treeOverview = new TreeNode(phone, accID, "", "#.aspx?platform=" + platName + "&product=" + phone, "_blank");
               tree1.ChildNodes.Add(treeOverview);
           }
      }
}