while 双从循环判断问题 急

Question

数据库结构 
reader---接点
reader1---子节点 直能取到  就是我判断有点问题烦 
 while(reader.Read())
        {
             //接点
            while (reader1.Read())
            {
                  //  子节点 
             }  
  }
要求 显示在XML 的格式 
<?xml version="1.0" encoding="utf-8"?>
<glasses_list name="项目">
  <titile projectname="土星" pid="1000">
    <titile1 buildingname="土星1" bid="1000">
<titile1 buildingname="土星2" bid="1000">
<titile1 buildingname="土星3" bid="1000">
    </titile1>
  </titile> <titile projectname="火星" pid="1000">
    <titile1 buildingname="火星1" bid="1000">
<titile1 buildingname="火星2" bid="1000">
<titile1 buildingname="火星3" bid="1000">
    </titile1>
  </titile>差不多 就这样了  就是 在 while 循环的时候 我 判断不了  

Answer 1

这个是我做的一个xml关于年份和年代的操作，希望对你有帮助
        lbyear.Items.Clear();
        string years = ddl_col_year.SelectedValue.ToString();
        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.Load(Server.MapPath("../year.xml"));
        XmlElement PersonService = xmlDoc.DocumentElement;
        XmlNodeList nodeList = PersonService.ChildNodes;
        int j, i;
        for (i = 0; i < nodeList.Count; i++)
        {
            string name = nodeList[i].Attributes["name"].Value;
            XmlNodeList yearlist = nodeList[i].ChildNodes;
            if (years == name)
            {
                for (j = 0; j < yearlist.Count; j++)
                {
                    string yearfei = yearlist[j].Attributes["name"].Value;
                    this.lbyear.Items.Insert(0, new ListItem(yearfei, yearfei));
                }            }
        }

Answer 2

没人回答吗？？？？？？？？？？？？ SqlDataReader reader = cmd.ExecuteReader();
        SqlDataReader reader1 = cmd1.ExecuteReader();        while(reader.Read())
        {            sb.Append(" <titile  projectname=\"" + reader["projectname"] + "\" pid=\"" + reader["pid"] + "\">");            
            while (reader1.Read())
            {
                if (reader1["pid"] == reader["pid"])
                {
                sb.Append(" <titile1  buildingname=\"" + reader1["buildingname"] + "\" bid=\"" + reader1["bid"] + "\">");
                sb.Append(" </titile1> ");
                // continue;
               }
        }
            sb.Append(" </titile> ");
            //break;
          //  continue;
        }

Answer 3

if (reader1["pid"] == reader["pid"])
            {
                while (reader1.Read())
                {                
                sb.Append(" <titile1  buildingname=\"" + reader1["buildingname"] + "\" bid=\"" + reader1["bid"] + "\">");
                sb.Append(" </titile1> ");             
               }
           }
reader1["pid"] 有异常啊 +
reader1["pid"] “reader1["pid"]”引发了“System.InvalidOperationException”类型的异常 object {System.InvalidOperationException}