下拉菜单内容为空
目的:从表中读取内容,生成下拉菜单
问题:下拉菜单是空的;
不知道错在那里
<script language="C#" runat="server">
SqlConnection conn;
void Page_Load(object sender, System.EventArgs e)
{
if (!IsPostBack)
{
//从数据库生成下拉菜单的内容
conn=new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"]);
string sql="select types from Brandtype";
SqlDataReader dr=null;
SqlCommand Cmd = new SqlCommand(sql, conn);
conn.Open();
dr= Cmd.ExecuteReader();
while (dr.Read())
{
types.Items.Add(new ListItem(dr["types"].ToString(),dr["types"].ToString()));
}
dr.Close();
conn.Close();
//结束
}
}
</script>
<asp:dropdownlist id="types" runat="server"></asp:dropdownlist>