请各路高手帮忙进来看一下，急了一下午的问题~~~~~~~~~~~~~~

通过读取数据库内的相应记录值,更改页面dropdownlist的当前选项页面组件布局ddl_kind1  ddl_field1  ddl_oper1  生成控件  ddl_next1
ddl_kind2  ddl_field2  ddl_oper2  生成控件  ddl_next2
ddl_kind3  ddl_field3  ddl_oper3  生成控件  ddl_next3
ddl_kind4  ddl_field4  ddl_oper4  生成控件  ddl_next4
ddl_kind5  ddl_field5  ddl_oper5  生成控件  代码:(private void changeddl())
string sql_cmd = "select info_id,field_code,operation,val,logical_operate,seq from t_query_condition where query_id=" + query_id;
SqlDataReader myreader = SqlHelper.ExecuteReader(sql_cmd);int j =1;
while (myreader.Read())
{
   string controlname = "ddl_kind"+j.ToString();
   ListItem item_temp = ((DropDownList)(this.FindControl(controlname))).Items.FindByValue(myreader.GetValue(0).ToString());
        //根据值查找页面ddl控件的项
   int index = ((DropDownList)(this.FindControl(controlname))).Items.IndexOf(item_temp);
       //获取该项在控件的位置
   ((DropDownList)(this.FindControl(controlname))).SelectedIndex = index;
       //在页面查找ddl_kind*控件，设置该控件的当前选项为该位置
   getfrommainddl(myreader.GetValue(0).ToString(),(DropDownList)(this.FindControl("ddl_field"+j.ToString())));
       //根扰ddl_kind*选项生成ddl_field控件项   controlname = "ddl_field"+j.ToString();
   item_temp = ((DropDownList)(this.FindControl(controlname))).Items.FindByValue(myreader.GetValue(1).ToString());
   index = ((DropDownList)(this.FindControl(controlname))).Items.IndexOf(item_temp);
   ((DropDownList)(this.FindControl(controlname))).SelectedIndex = index;   controlname = "ddl_oper"+j.ToString();
   item_temp = ((DropDownList)(this.FindControl(controlname))).Items.FindByValue(myreader.GetValue(2).ToString());
   index = ((DropDownList)(this.FindControl(controlname))).Items.IndexOf(item_temp);
  ((DropDownList)(this.FindControl(controlname))).SelectedIndex = index;
   
   if (j<=4)
    {
controlname = "ddl_next"+j.ToString();
item_temp = ((DropDownList)(this.FindControl(controlname))).Items.FindByValue(myreader.GetValue(4).ToString());
index = ((DropDownList)(this.FindControl(controlname))).Items.IndexOf(item_temp);
((DropDownList)(this.FindControl(controlname))).SelectedIndex = index;
    }
    j++;
}
myreader.Close();for (int n = 1;n < 6;n++)
{
m.rw(((DropDownList)(this.FindControl("ddl_kind"+Convert.ToString(n)))).SelectedItem.Text);
}问题:页面所有ddl_kind的当前选项为myreader循环后最一条记录对应的值，如果改为if(myreader())运行时，刚所有ddl_kind*控件当前项均为第一条记录所对应的项