关于下拉列表的求救
for (int i = 0; i < NavigateTree.InfinityTree.Rows.Count; i++)
  {
  ClassDrop.Items.Add(NavigateTree.InfinityTree.Rows[i]["StrTree"].ToString());
  ClassDrop.Items[i].Value = NavigateTree.InfinityTree.Rows[i]["Classid"].ToString();
  }
  ClassDrop.Items.Insert(0, "一级分类");
  ClassDrop.Items[0].Value = "0";

 Connection = new OleDbConnection(DataProvider.ConnectionString);
  Command = new OleDbCommand();
  Command.Connection = Connection;
  Command.CommandText = "Select * From aClass where Classid=" + ClassDrop.SelectedValue;
  Connection.Open();
  dr= Command.ExecuteReader();

为什么ClassDrop.SelectedValue选出来的为空??

------解决方案--------------------
for (int i = 0; i < NavigateTree.InfinityTree.Rows.Count; i++) 
{ 
ClassDrop.Items.Add(NavigateTree.InfinityTree.Rows[i]["StrTree"].ToString()); 
ClassDrop.Items[i].Value = NavigateTree.InfinityTree.Rows[i]["Classid"].ToString(); 
} 
ClassDrop.Items.Insert(0, "一级分类"); 
ClassDrop.Items[0].Value = "0"; 
===========================================
只往里添加了。也没有选择阿

另外，添加的时候value和text为什么要分开呢

ListItem itm=new ListItem(value,text);
ClassDrop.Items.Add(itm);