DropDownList1用了Atlas后，为什么不能增加选项了。
用户控件里的代码　ddl.ascx

<table>
<tr>
<td>
<asp:DropDownList ID= "DropDownList1 " runat= "server " AutoPostBack= "True " OnSelectedIndexChanged= "DropDownList1_SelectedIndexChanged ">
</asp:DropDownList> <asp:RequiredFieldValidator ID= "RequiredFieldValidator2 " runat= "server " ControlToValidate= "DropDownList1 "
ErrorMessage= "RequiredFieldValidator "> * </asp:RequiredFieldValidator> </td>
<td>
<atlas:UpdatePanel ID= "UpdatePanel1 " runat= "server ">
<ContentTemplate>
  <asp:DropDownList ID= "DropDownList2 " runat= "server ">
</asp:DropDownList>
<asp:RequiredFieldValidator ID= "RequiredFieldValidator1 " runat= "server " ControlToValidate= "DropDownList2 "
ErrorMessage= "RequiredFieldValidator "> * </asp:RequiredFieldValidator>
</ContentTemplate>
<Triggers>
<atlas:ControlEventTrigger ControlID= "DropDownList1 " EventName= "SelectedIndexChanged " />
</Triggers>
</atlas:UpdatePanel>
</td>
</tr>
</table>


cs代码


SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings[ "publ "].ConnectionString);
SqlDataAdapter sda = new SqlDataAdapter();

sda.SelectCommand = new SqlCommand( "SELECT [lbid], [lbname] FROM [info_lb] ", con);
DataSet ds = new DataSet();
sda.Fill(ds, "lbname ");

DropDownList1.DataSource = ds.Tables[ "lbname "];
DropDownList1.DataValueField = "lbid ";
DropDownList1.DataTextField = "lbname ";
DropDownList1.DataBind();
DropDownList1.Items.Insert(0, new ListItem( "请选择分类 ", " "));
con.Close();

请选择分类这项加不进去，运行后没有这项，也没有出错。

[解决办法]
应该先添加到表里面，然后再绑定
[解决办法]
<asp:DropDownList ID= "DropDownList1 " runat= "server " AppendDataBoundItems= "True ">
<asp:ListItem Value= "0 "> 请选择分类 </asp:ListItem> </asp:DropDownList>


cs:
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings[ "publ "].ConnectionString);
SqlDataAdapter sda = new SqlDataAdapter();
sda.SelectCommand = new SqlCommand( "SELECT [lbid], [lbname] FROM [info_lb] ", con);
DataSet ds = new DataSet();
sda.Fill(ds, "lbname ");

DropDownList1.DataSource = ds.Tables[ "lbname "];
DropDownList1.DataValueField = "lbid ";
DropDownList1.DataTextField = "lbname ";
DropDownList1.DataBind();
con.Close();

加上AppendDataBoundItems= "True "这个属性，［请选择分类］会出现在下拉菜单的第一项