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How to: Programmatically Enumerate Site-Map Nodes

You can use navigation controls to add site navigation to your Web pages with little or no code, but you can also work with site navigation programmatically. When your Web application runs, ASP.NET creates a SiteMap object that reflects the structure of the site map. The SiteMap object, in turn, exposes a collection of SiteMapNode objects that contain properties for each node in the site map.

Navigation controls such as the SiteMapPath control work with the SiteMap and SiteMapNode objects to render the appropriate links automatically.

You can use the SiteMap and SiteMapNode objects in your own code to create custom navigation.

The following code example shows how to display the titles of all of the child nodes for the current page, as long as the current page is listed in the site-map file. If the current page is not listed in the site-map file, the first line of code that uses the SiteMap object will cause a NullReferenceException exception.

<%@ Page language="c#" AutoEventWireup="true" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

  private void Page_Load(object sender, System.EventArgs e)
  {
    try
    {
      string LabelText = "";

      // Displays the title of the current node.
      Label_CurrentNode.Text = SiteMap.CurrentNode.Title;

      // Determines if the current node has child nodes.
      if (SiteMap.CurrentNode.HasChildNodes)
      {
        foreach (SiteMapNode childNodesEnumerator in SiteMap.CurrentNode.ChildNodes)
        {
          // Displays the title of each node.
          LabelText = LabelText + childNodesEnumerator.Title + "<br />";
        }
      }

      Label_ChildNodes.Text = LabelText;
    }
    catch (System.NullReferenceException ex)
    {
      Label_CurrentNode.Text = "The current file is not in the site map.";
    }
    catch (Exception ex)
    {
      Label_CurrentNode.Text = "Generic exception: " + e.ToString();
    }
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Enumerating Child Site Map Nodes</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

      <h2>Current Node</h2>
      <asp:Label id="Label_CurrentNode" runat="Server"></asp:Label>

      <h2>Child Nodes</h2>
      <asp:Label id="Label_ChildNodes" runat="Server"></asp:Label>

      <h2>Verify Against Site Map</h2>
      <asp:SiteMapDataSource id="SiteMapDataSource1" runat="server" />
      <asp:TreeView id="TreeView1" runat="server" dataSourceID="SiteMapDataSource1">
      </asp:TreeView>

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


You can hide the links in your navigation structure from users in specified security roles. For more information, see ASP.NET Site-Map Security Trimming.

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