ASP.NET

System.Xml.Serialization.XmlRootAttribute xRoot = new System.Xml.Serialization.XmlRootAttribute();
             xRoot.ElementName = "EnvironmentConfigurations";
             xRoot.IsNullable = true;
             System.Xml.Serialization.XmlSerializer ser = new System.Xml.Serialization.XmlSerializer(typeof(<your Type>), xRoot);
             <your type> x  = (<your Type>)ser.Deserialize(new System.IO.StringReader(<your xml>));

 <asp:DropDownList ID="ddl" runat="server"></asp:DropDownList>

ConnectionStringSettingsCollection a = ConfigurationManager.ConnectionStrings;
        ListItem lst = new ListItem();
        foreach (ConnectionStringSettings s in a)
        {
            lst = new ListItem(s.ConnectionString, s.ConnectionString);
            ddl.Items.Add(lst);
        }
        ddl.Items.RemoveAt(0);