<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="CustomDropDown.ascx.cs" Inherits="Mirabeau.CustomCmsDataTypes.UserControlls.CustomDropDown" %>
<asp:DropDownList id="drop1" runat="server">
    <asp:ListItem>Item 1</asp:ListItem>
    <asp:ListItem>Item 2</asp:ListItem>
    <asp:ListItem>Item 3</asp:ListItem>
    <asp:ListItem>Item 4</asp:ListItem>
    <asp:ListItem>Item 5</asp:ListItem>
    <asp:ListItem>Item 6</asp:ListItem>
</asp:DropDownList>
<asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" />

<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>


--------------


using System;


namespace Mirabeau.CustomCmsDataTypes.UserControlls
{
    public partial class CustomDropDown : System.Web.UI.UserControl, umbraco.editorControls.userControlGrapper.IUsercontrolDataEditor
    {

        public object value
        {
            get
            {
                return drop1.SelectedValue;
            }
            set
            {
                drop1.SelectedValue = value.ToString();
            }
        }

        protected void Page_Load(object sender, EventArgs e)
        {
            if (Page.IsPostBack)
            {

            }
        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            string dropDownValue = string.Empty;
            dropDownValue = value.ToString();
            Label1.Text = "You have selected this" + dropDownValue;
        }
    }
}