- c#一段代码, 逻辑上有一句 if 有没有都可以,可是去掉就会报错堆栈溢出,加上就没事,大神帮忙看看是什么原因
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string str_cnn = "provider=Microsoft.Jet.OLEDB.4.0; Data Source=";
string str_stringfile = "mdb\mydb.mdb";
OleDbCommand cmd;
OleDbConnection cnn;
OleDbDataReader reader;
string str_sql;string str_conn = str_cnn + MapPath(str_stringfile); cnn = new OleDbConnection(str_conn); str_sql = "SELECT t_menuL0.*, t_menuL1.* FROM t_menuL1 RIGHT JOIN t_menuL0 ON t_menuL1.m1_m0id = t_menuL0.m0_id"; cnn.Open(); cmd = new OleDbCommand(str_sql,cnn); reader = cmd.ExecuteReader();//以上是数据库的连接和读取
Panel pl_fenlei, pl_fenleixinwen, pl_cr;
HyperLink hl_xiangmu,hl_fenlei;
//这里定义了几个控件用来添加到前台的 下面是数据读取的循环
while (reader.Read()) {
if (FindControl((div_mainm0id.ID).ToString() + "_" + reader["m0_id"].ToString()) == null) {
// 用m0_id 字段创建对应控件, 但是在数据库中有重复出现,所以要检测
hl_fenlei = new HyperLink();
hl_fenlei.Text = reader["m0_ttl"].ToString();pl_fenlei = new Panel(); pl_fenlei.ID = (div_mainm0id.ID).ToString() + "_" + reader["m0_id"].ToString(); pl_fenlei.CssClass = "fenlei"; pl_fenlei.Controls.Add(hl_fenlei); pl_fenleixinwen = new Panel(); pl_fenleixinwen.ID = "fenleixinwen" + "_" + reader["m0_id"].ToString(); pl_fenleixinwen.CssClass = "fenleixinwen"; pl_fenlei.Controls.Add(pl_fenleixinwen); div_mainm0id.Controls.Add(pl_fenlei); } hl_xiangmu = new HyperLink(); hl_xiangmu.Text=reader["m1_ttl"].ToString(); if (FindControl("fenleixinwen_" + reader["m1_m0id"].ToString())!=null) { ((Panel)FindControl("fenleixinwen_" + reader["m1_m0id"].ToString())).Controls.Add(hl_xiangmu); } // 问题就出在上面的if语句了 } cnn.Close();// 前台代码什么都没有 就定义了div标签 向标签里面添加数据 <body> <form id="form1" runat="server"> <div> <div runat="server" id="div_mainm0id"> </div> </div> <div id="div1"></div> </form> </body>
