MenuItem Class

A Menu control is made up of a hierarchy of menu items represented by MenuItem objects. Each menu item has a read-only Depth property that specifies the level at which the menu item is displayed in the Menu control. Menu items at the top level (level 0) that do not have a parent menu item are called root menu items. A menu item that has a parent menu item is called a submenu item. All root menu items are stored in the Items collection. Submenu items are stored in a parent menu item's ChildItems collection. You can access a menu item's parent menu item by using the Parent property.

Note
The Items and ChildItems collections contain only the menu items for the next level down. To access menu items further down the menu tree, use the ChildItems property of a subsequent menu item.

To create the menu items for a Menu control, use one of the following methods:

Use declarative syntax to create static menu items.

Use a constructor to dynamically create new instances of the MenuItem class. These MenuItem objects can then be added to the Items or ChildItems collection.

Bind the Menu control to a data source. When the Menu control is bound to a SiteMapDataSource control, MenuItem objects are automatically created that correspond to the items in the data source. For other data sources, MenuItem objects are also automatically created that match the hierarchy structure of data source; however, you must also use the DataBindings collection to define the menu item bindings that specify the binding relationship between a menu item and its corresponding data item.

The menu items are displayed in either a static menu or a dynamic menu, depending on its level. The static menu is always displayed in a Menu control. By default, the menu items at the top level (level 0) are displayed in the static menu. You can display additional menu levels (static submenus) within the static menu by setting the StaticDisplayLevels property. Menu items (if any) with a higher level than the value specified by the StaticDisplayLevels property are displayed in a dynamic submenu. A dynamic submenu appears only when the user positions the mouse pointer over the parent menu item that contains a dynamic submenu.

When the user clicks a menu item, the Menu control can either navigate to a linked Web page or simply post back to the server. If the NavigateUrl property of a menu item is set, the Menu control navigates to the linked page; otherwise, it posts the page back to the server for processing. By default, a linked page is displayed in the same window or frame as the Menu control. To display the linked content in a different window or frame, use the Target property of the Menu control.

Note
The Menu.Target property affects every menu item in the control. To specify a window or frame for an individual menu item, set the Target property of the MenuItem object directly.

Each menu item has a Text and a Value property. The value of the Text property is displayed in the Menu control, while the Value property is used to store any additional data about the menu item, such as data passed to the postback event associated with the menu item. If you set the Text property, but leave the Value property unset, the Value property is automatically set with the same value as the Text property. The opposite is also true. If you set the Value property, but not the Text property, the Text property is automatically set with the same value as the Value property.

Note
Menu items at the same menu level must each have a unique value for the Value property; the Menu control cannot distinguish between different menu items at the same level that have the same value. In this scenario, if the user clicks a menu item that has a duplicate value, the menu item that appears first in the menu is selected.

To display a ToolTip when the user positions the mouse pointer over a menu item, set the item's ToolTip property.

A Menu control has several different types of menu items. You can control the style (such as font size and color) for the different menu item types by using the properties in the following table.

Instead of setting the individual style properties, you can specify styles that are applied to menu items based on their level by using the style collections shown in the following table.

The first style in the collection corresponds to the style of the menu items at the first depth level in the menu tree. The second style in the collection corresponds to the style of the menu items at the second depth level in the menu tree, and so on. This is most often used to generate table of contents-style navigation menus where menu items at a certain depth should have the same appearance, regardless of whether they have submenus.

Note
If you use any of the level style collections listed in the previous table to define the style for the Menu control, these style settings override the individual menu item style properties.

In addition to customizing a menu item's style, you can also customize its appearance. You can specify custom images for the different parts for a menu item by setting the properties in the following table.

To determine whether a menu item is currently selected in a Menu control, use the Selected property. You can also determine whether a menu item is bound to data by using the DataBound property. If a menu item is bound to data, you can use the DataItem property to access the values of the data item bound to the menu item.

For a list of initial property values for an instance of the MenuItem class, see the MenuItem constructor.

The following example demonstrates how to populate a Menu control with static MenuItem objects using declarative syntax.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>MenuItem Declarative Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>MenuItem Declarative Example</h3>

      <!-- Use declarative syntax to create the   -->
      <!-- menu structure. Create submenu items   -->
      <!-- by nesting them within parent menu     -->
      <!-- items.                                 -->
      <asp:menu id="NavigationMenu"
        staticdisplaylevels="1"
        staticsubmenuindent="10" 
        orientation="Vertical" 
        target="_blank"  
        runat="server">

        <items>
          <asp:menuitem navigateurl="Home.aspx" 
            text="Home"
            imageurl="Images\Home.gif"
            popoutimageurl="Images\Popout.jpg"   
            tooltip="Home">
            <asp:menuitem navigateurl="Music.aspx"
              text="Music"
              popoutimageurl="Images\Popout.jpg"
              tooltip="Music">
              <asp:menuitem navigateurl="Classical.aspx" 
                text="Classical"
                separatorimageurl="Images\Separator.jpg"
                tooltip="Classical"/>
              <asp:menuitem navigateurl="Rock.aspx"
                text="Rock"
                separatorimageurl="Images\Separator.jpg"
                tooltip="Rock"/>
              <asp:menuitem navigateurl="Jazz.aspx"
                text="Jazz"
                separatorimageurl="Images\Separator.jpg"
                tooltip="Jazz"/>
            </asp:menuitem>
            <asp:menuitem navigateurl="Movies.aspx"
              text="Movies"
              popoutimageurl="Images\Popout.jpg"              
              tooltip="Movies">
              <asp:menuitem navigateurl="Action.aspx"
                text="Action"
                separatorimageurl="Images\Separator.jpg"
                tooltip="Action"/>
              <asp:menuitem navigateurl="Drama.aspx"
                text="Drama"
                separatorimageurl="Images\Separator.jpg"
                tooltip="Drama"/>
              <asp:menuitem navigateurl="Musical.aspx"
                text="Musical"
                separatorimageurl="Images\Separator.jpg"
                tooltip="Musical"/>
            </asp:menuitem>
          </asp:menuitem>
        </items>

      </asp:menu>

    </form>
  </body>
</html>

The following example demonstrates how to bind a Menu control to a SiteMapDataSource control. When bound to a data source, the Menu control automatically creates the MenuItem objects. For this example to work correctly, you must copy the sample site map data below to a file named Web.sitemap.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

  <!-- For the hover styles of the Menu control to  -->
  <!-- work correctly, you must include this head   -->
  <!-- element.                                     -->
  <head runat="server">
    <title>Menu DataBinding Example</title>
</head>

  <body>
    <form id="form1" runat="server">

      <h3>Menu DataBinding Example</h3>

      <!-- Bind the Menu control to a SiteMapDataSource control.  -->
      <asp:menu id="NavigationMenu"
        disappearafter="2000"
        staticdisplaylevels="2"
        staticsubmenuindent="10" 
        orientation="Vertical"
        font-names="Arial" 
        target="_blank"
        datasourceid="MenuSource"   
        runat="server">

        <staticmenuitemstyle backcolor="LightSteelBlue"
          forecolor="Black"/>
        <statichoverstyle backcolor="LightSkyBlue"/>
        <dynamicmenuitemstyle backcolor="Black"
          forecolor="Silver"/>
        <dynamichoverstyle backcolor="LightSkyBlue"
          forecolor="Black"/>

      </asp:menu>

      <asp:SiteMapDataSource id="MenuSource"
        runat="server"/>        

    </form>
  </body>
</html>

The following is sample site map data for the previous example.

<siteMap>

<siteMapNode url="~\Home.aspx"

title="Home"

description="Home">

<siteMapNode url="~\Music.aspx"

title="Music"

description="Music">

<siteMapNode url="~\Classical.aspx"

title="Classical"

description="Classical"/>

<siteMapNode url="~\Rock.aspx"

title="Rock"

description="Rock"/>

<siteMapNode url="~\Jazz.aspx"

title="Jazz"

description="Jazz"/>

</siteMapNode>

<siteMapNode url="~\Movies.aspx"

title="Movies"

description="Movies">

<siteMapNode url="~\Action.aspx"

title="Action"

description="Action"/>

<siteMapNode url="~\Drama.aspx"

title="Drama"

description="Drama"/>

<siteMapNode url="~\Musical.aspx"

title="Musical"

description="Musical"/>

</siteMapNode>

</siteMapNode>

</siteMap>

.NET Framework

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference