1 <asp:ScriptManager ID="ScriptManager1" runat="server" /> 2                        <br /> 3             <asp:TextBox ID="TextBox1" runat="server" Width="300px">Select an option.</asp:TextBox> 4             <asp:Label ID="TextLabel" runat="server" Text="Select an option." Width="303px"></asp:Label> 5             <asp:Panel ID="DropPanel" runat="server" CssClass="ContextMenuPanel" Style="display :none; visibility: hidden;"> 6                 <asp:LinkButton ID="Option1" runat="server" Text="Option 1" CssClass="ContextMenuItem" OnClick="OnSelect" /> 7                 <asp:LinkButton ID="Option2" runat="server" Text="Option 2" CssClass="ContextMenuItem" OnClick="OnSelect" /> 8                 <asp:LinkButton ID="Option3" runat="server" Text="Option 3 (Click Me !)" CssClass="ContextMenuItem" OnClick="OnSelect" /> 9                10             </asp:Panel>11             <ajaxToolkit:DropDownExtender ID="DDE" runat="server" TargetControlID="TextBox1" DropDownControlID="DropPanel">12             </ajaxToolkit:DropDownExtender>    13             14             <br /><br /><br />15             16             <asp:UpdatePanel ID="UpdatePanel1" runat="server">17             <ContentTemplate>18                 <asp:Label ID="lblSelection" runat="server" Text=""></asp:Label> 19             </ContentTemplate>20             <Triggers>21                 <asp:AsyncPostBackTrigger ControlID="Option1" EventName="Click" />22                 <asp:AsyncPostBackTrigger ControlID="Option2" EventName="Click" />23                 <asp:AsyncPostBackTrigger ControlID="Option3" EventName="Click" />24             </Triggers>25             </asp:UpdatePanel>

 protected void OnSelect(object sender, EventArgs e)    {        lblSelection.Text = "You selected <b>" + ((LinkButton)sender).Text + "</b>.";    }

 1 .ContextMenuPanel  2 { 3     border: 1px solid #868686; 4     z-index: 1000; 5     background: url(images/menu-bg.gif) repeat-y 0 0 #FAFAFA; 6     cursor: default; 7     padding: 1px 1px 0px 1px; 8     font-size: 11px; 9 }10 11 .ContextMenuBreak12 {13     margin:1px 1px 1px 32px;14     padding:0;15     height:1px;16     overflow:hidden;17     display:block;18     border-top: 1px solid #C5C5C5;    19 }20 21 a.ContextMenuItem22 {23     margin: 1px 0 1px 0;24     display: block;25     color: #003399;26     text-decoration: none;27     cursor: pointer;    28     padding: 4px 19px 4px 33px;29     white-space: nowrap;30 }31 32 a.ContextMenuItem-Selected33 {34     font-weight: bold;35 }36 37 a.ContextMenuItem:hover38 {39     background-color: #FFE6A0;40     color: #003399;41     border: 1px solid #D2B47A;42     padding: 3px 18px 3px 32px;43 }