asp.net2008(C#)的TreeView1添加树型目录节点

//添加树型目录节点
public void LoadTree()
{
    DataSet ds = bll.TreeNodes();   --获取数据源(工号,姓名,部门码,部门名称)
    DataSet ds2=ds;
    TreeNode rootNode,tmpNode;
    DataRow dr,dr2;
    string strTemp = "";
    string strDept = "";
   
    for (int i = 0; i <= ds.Tables[0].Rows.Count-1; i++)
    {
        dr = ds.Tables[0].Rows[i];
        rootNode = new TreeNode();
        rootNode.Value = dr[2].ToString();
        rootNode.Text = dr[3].ToString();
        strDept = dr[2].ToString();
        if (strDept != strTemp)
        {
            for (int j = 0; j <= ds2.Tables[0].Rows.Count - 1; j++)
            {
                dr2 = ds2.Tables[0].Rows[j];
                tmpNode = new TreeNode();
                if (dr2[2].ToString() == strDept)
                {
                    tmpNode.Value = dr2[0].ToString();
                    tmpNode.Text = dr2[1].ToString();
                    rootNode.ChildNodes.Add(tmpNode);
                }
            }
            rootNode.Expanded = false;
            TreeView1.Nodes.Add(rootNode);
        }
        strTemp = strDept;
    }
}