Check this sample it works fine for me. I get proper value
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<asp:DropDownList ID="DropDownList1" runat="server">
</asp:DropDownList>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick = "Button1_Click" />
</form>
</body>
</html>
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataSet ds = new DataSet();
string url = "http://letitgo.asia/api/serviceData.go?apimode=test&goid=5011000001&password=test123&rtype=xml&service_family=02";
System.Net.WebRequest request = System.Net.WebRequest.Create(url);
using (System.Net.WebResponse response = (System.Net.HttpWebResponse)request.GetResponse())
{
using (System.IO.StreamReader reader = new System.IO.StreamReader(response.GetResponseStream(), Encoding.UTF8))
{
ds.ReadXml(reader);
DropDownList1.DataSource = ds;
DropDownList1.DataTextField = "operator_name";
DropDownList1.DataValueField = "operator_code";
DropDownList1.DataBind();
DropDownList1.Items.Insert(0, new ListItem("Select", ""));
}
}
}
}
protected void Button1_Click(object sender, EventArgs e)
{
Response.Write("Text: " + DropDownList1.SelectedItem.Text + "Value: " + DropDownList1.SelectedItem.Value);
}