MenuEventHandler Delegate
Assembly: System.Web (in system.web.dll)
'Declaration Public Delegate Sub MenuEventHandler ( _ sender As Object, _ e As MenuEventArgs _ ) 'Usage Dim instance As New MenuEventHandler(AddressOf HandlerMethod)
/** @delegate */ public delegate void MenuEventHandler ( Object sender, MenuEventArgs e )
Not applicable.
Parameters
- sender
The source of the event.
- e
A MenuEventArgs that contains the event data.
The MenuEventHandler class is used to represent the method that handles the events in the following table.
| Event | Description |
|---|---|
| MenuItemClick | Occurs when a menu item is clicked. This event is commonly used to synchronize a Menu control with another control on the page. |
| MenuItemDataBound | Occurs when a menu item is bound to data. This event is commonly used to modify a menu item before it is rendered in a Menu control. |
When you create a MenuEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Events and Delegates.
The following code example demonstrates how to use the MenuEventHandler delegate to programmatically register an event handler for the MenuItemClick event of a Menu control. For this example to work correctly, you must copy the sample site map data below to a file named Web.sitemap.
<%@ Page Language="VB" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) ' Create a new Menu control. Dim newMenu As New Menu() ' Set the properties of the Menu control. newMenu.ID = "NavigationMenu" newMenu.Orientation = Orientation.Vertical newMenu.Target = "_blank" ' Specify the data source for the menu. newMenu.DataSourceID = "MenuSource" ' Programmatically register the event-handling method ' for the MenuItemClick event of a Menu control. AddHandler newMenu.MenuItemClick, AddressOf NavigationMenu_MenuItemClick ' Add the Menu control to the Controls collection ' of the PlaceHolder control. MenuPlaceHolder.Controls.Add(newMenu) End Sub Sub NavigationMenu_MenuItemClick(ByVal sender As Object, ByVal e As MenuEventArgs) ' Display the text of the menu item selected by the user. Message.Text = "You selected " & e.Item.Text & "." End Sub </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>MenuEventHandler Example</title> </head> <body> <form id="form1" runat="server"> <h3>MenuEventHandler Example</h3> <asp:placeholder id="MenuPlaceHolder" runat="server"/> <asp:sitemapdatasource id="MenuSource" runat="server"/> <hr/> <asp:label id="Message" runat="server"/> </form> </body> </html>
The following is sample site map data for the previous example.
<siteMap>
<siteMapNode title="Home"
description="Home">
<siteMapNode title="Music"
description="Music">
<siteMapNode title="Classical"
description="Classical"/>
<siteMapNode title="Rock"
description="Rock"/>
<siteMapNode title="Jazz"
description="Jazz"/>
</siteMapNode>
<siteMapNode title="Movies"
description="Movies">
<siteMapNode title="Action"
description="Action"/>
<siteMapNode title="Drama"
description="Drama"/>
<siteMapNode title="Musical"
description="Musical"/>
</siteMapNode>
</siteMapNode>
</siteMap>