SiteMapProvider Class
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SiteMapProvider Class

 

Provides a common base class for all site map data providers, and a way for developers to implement custom site map data providers that can be used with the ASP.NET site map infrastructure as persistent stores for SiteMap objects.

Namespace:   System.Web
Assembly:  System.Web (in System.Web.dll)


public abstract class SiteMapProvider : ProviderBase

NameDescription
System_CAPS_protmethodSiteMapProvider()

Initializes a new instance of the SiteMapProvider class.

NameDescription
System_CAPS_pubpropertyCurrentNode

Gets the SiteMapNode object that represents the currently requested page.

System_CAPS_pubpropertyDescription

Gets a brief, friendly description suitable for display in administrative tools or other user interfaces (UIs).(Inherited from ProviderBase.)

System_CAPS_pubpropertyEnableLocalization

Gets or sets a Boolean value indicating whether localized values of SiteMapNode attributes are returned.

System_CAPS_pubpropertyName

Gets the friendly name used to refer to the provider during configuration.(Inherited from ProviderBase.)

System_CAPS_pubpropertyParentProvider

Gets or sets the parent SiteMapProvider object of the current provider.

System_CAPS_pubpropertyResourceKey

Get or sets the resource key that is used for localizing SiteMapNode attributes.

System_CAPS_pubpropertyRootNode

Gets the root SiteMapNode object of the site map data that the current provider represents.

System_CAPS_pubpropertyRootProvider

Gets the root SiteMapProvider object in the current provider hierarchy.

System_CAPS_pubpropertySecurityTrimmingEnabled

Gets a Boolean value indicating whether a site map provider filters site map nodes based on a user's role.

NameDescription
System_CAPS_protmethodAddNode(SiteMapNode)

Adds a SiteMapNode object to the node collection that is maintained by the site map provider.

System_CAPS_protmethodAddNode(SiteMapNode, SiteMapNode)

Adds a SiteMapNode object to the node collection that is maintained by the site map provider and specifies the parent SiteMapNode object.

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodFindSiteMapNode(HttpContext)

Retrieves a SiteMapNode object that represents the currently requested page using the specified HttpContext object.

System_CAPS_pubmethodFindSiteMapNode(String)

When overridden in a derived class, retrieves a SiteMapNode object that represents the page at the specified URL.

System_CAPS_pubmethodFindSiteMapNodeFromKey(String)

Retrieves a SiteMapNode object based on a specified key.

System_CAPS_pubmethodGetChildNodes(SiteMapNode)

When overridden in a derived class, retrieves the child nodes of a specific SiteMapNode.

System_CAPS_pubmethodGetCurrentNodeAndHintAncestorNodes(Int32)

Provides an optimized lookup method for site map providers when retrieving the node for the currently requested page and fetching the parent and ancestor site map nodes for the current page.

System_CAPS_pubmethodGetCurrentNodeAndHintNeighborhoodNodes(Int32, Int32)

Provides an optimized lookup method for site map providers when retrieving the node for the currently requested page and fetching the site map nodes in the proximity of the current node.

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetParentNode(SiteMapNode)

When overridden in a derived class, retrieves the parent node of a specific SiteMapNode object.

System_CAPS_pubmethodGetParentNodeRelativeToCurrentNodeAndHintDownFromParent(Int32, Int32)

Provides an optimized lookup method for site map providers when retrieving an ancestor node for the currently requested page and fetching the descendant nodes for the ancestor.

System_CAPS_pubmethodGetParentNodeRelativeToNodeAndHintDownFromParent(SiteMapNode, Int32, Int32)

Provides an optimized lookup method for site map providers when retrieving an ancestor node for the specified SiteMapNode object and fetching its child nodes.

System_CAPS_protmethodGetRootNodeCore()

When overridden in a derived class, retrieves the root node of all the nodes that are currently managed by the current provider.

System_CAPS_protmethodSystem_CAPS_staticGetRootNodeCoreFromProvider(SiteMapProvider)

Retrieves the root node of all the nodes that are currently managed by the specified site map provider.

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodHintAncestorNodes(SiteMapNode, Int32)

Provides a method that site map providers can override to perform an optimized retrieval of one or more levels of parent and ancestor nodes, relative to the specified SiteMapNode object.

System_CAPS_pubmethodHintNeighborhoodNodes(SiteMapNode, Int32, Int32)

Provides a method that site map providers can override to perform an optimized retrieval of nodes found in the proximity of the specified node.

System_CAPS_pubmethodInitialize(String, NameValueCollection)

Initializes the SiteMapProvider implementation, including any resources that are needed to load site map data from persistent storage.(Overrides ProviderBase.Initialize(String, NameValueCollection).)

System_CAPS_pubmethodIsAccessibleToUser(HttpContext, SiteMapNode)

Retrieves a Boolean value indicating whether the specified SiteMapNode object can be viewed by the user in the specified context.

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethodRemoveNode(SiteMapNode)

Removes the specified SiteMapNode object from the node collection that is maintained by the site map provider.

System_CAPS_protmethodResolveSiteMapNode(HttpContext)

Raises the SiteMapResolve event.

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

NameDescription
System_CAPS_pubeventSiteMapResolve

Occurs when the CurrentNode property is called.

The StaticSiteMapProvider and XmlSiteMapProvider classes represent the default implementations of the abstract SiteMapProvider class. The XmlSiteMapProvider uses an XML file named Web.sitemap to store site map data. For more information on about the Web.sitemap file, see ASP.NET Site Maps.

The SiteMapProvider class supports the concept of a site map provider hierarchy, by declaring the RootProvider and ParentProvider properties. A SiteMapProvider can be a child or parent of another provider. This enables scenarios where different content areas of a site are owned or implemented by different development groups that maintain their own site maps and site map providers.

All SiteMapProvider objects are configured in the Web.config files. Any site map providers that are declared in these configuration files are loaded at run time and are used to load and process site navigation data. The SiteMap object, which keeps track of all the providers that are available to it through its Providers property collection, provides programmatic access to the navigation data that is managed by the providers. The following code example demonstrates the format that is used to declare a site map provider in a Web.config file.

<siteMap defaultProvider="<name>">
  <providers>
    <add
      name="<friendly name>"
      type="<fully qualified class name>, <assembly name (optional)>" 
      siteMapFile = "<file name>" />
  </providers>
</siteMap>

The site navigation data that is loaded by these providers is used by other components of the site map infrastructure, such as the SiteMapPath and TreeView controls, to display site map information for users.

If you implement your own site map provider, you can place the source file in the App_Code directory of your ASP.NET application, and then the assembly will be compiled automatically. You can also place your own site map provider in the Global Assembly Cache (GAC), and provide a fully-qualified reference to it in the Web.config file. For more information on compiler services, see Working with Assemblies and the Global Assembly Cache.

Notes to Inheritors:

When you inherit from the SiteMapProvider class, you must override the following members: GetRootNodeCore, FindSiteMapNode, GetChildNodes, and GetParentNode.

The following code example demonstrates how to write a class that implements the abstract SiteMapProvider class. This example includes only a sample SiteMapProvider and a sample text file that works with it. To run the example you also need an entry in the Web.config file and an .aspx page. You can find these in the documentation for the SiteMapDataSource.SiteMapProvider property.

The example uses a comma-delimited file that follows an expected structure to load sitemap information. The first line of the file represents the root node of the sitemap, and subsequent lines are subnodes. Each subnode identifies its parent node by URL. An example of a file that meets these criteria is shown below.

default.aspx,Home,MyCompany Home Page,
sale.aspx,Now On Sale,Check Out These Great Deals!,default.aspx
catalog.aspx,Online Catalog,Browse Our Many Great Items!,default.aspx

The SimpleTextSiteMapProvider provides example implementations of all the SiteMapProvider properties and methods.

using System;
using System.Configuration.Provider;
using System.Collections;
using System.Collections.Specialized;
using System.IO;
using System.Security.Permissions;
using System.Web;

namespace Samples.AspNet.CS
{

  [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
  public class SimpleTextSiteMapProvider : SiteMapProvider
  {
    private SiteMapProvider parentSiteMapProvider = null;
    private string simpleTextProviderName = null;
    private string sourceFilename = null;
    private SiteMapNode rootNode = null;
    private ArrayList siteMapNodes = null;
    private ArrayList childParentRelationship = null;


    // A default constructor. The Name property is initialized in the
    // Initialize method.
    public SimpleTextSiteMapProvider()
    {
    }
    // Implement the CurrentNode property.
    public override SiteMapNode CurrentNode
    {
      get
      {
        string currentUrl = FindCurrentUrl();
        // Find the SiteMapNode that represents the current page.
        SiteMapNode currentNode = FindSiteMapNode(currentUrl);
        return currentNode;
      }
    }

    // Implement the RootNode property.
    public override SiteMapNode RootNode
    {
      get
      {
        return rootNode;
      }
    }
    // Implement the ParentProvider property.
    public override SiteMapProvider ParentProvider
    {
      get
      {
        return parentSiteMapProvider;
      }
      set
      {
        parentSiteMapProvider = value;
      }
    }

    // Implement the RootProvider property.
    public override SiteMapProvider RootProvider
    {
      get
      {
        // If the current instance belongs to a provider hierarchy, it
        // cannot be the RootProvider. Rely on the ParentProvider.
        if (this.ParentProvider != null)
        {
          return ParentProvider.RootProvider;
        }
        // If the current instance does not have a ParentProvider, it is
        // not a child in a hierarchy, and can be the RootProvider.
        else
        {
          return this;
        }
      }
    }
    // Implement the FindSiteMapNode method.
    public override SiteMapNode FindSiteMapNode(string rawUrl)
    {

      // Does the root node match the URL?
      if (RootNode.Url == rawUrl)
      {
        return RootNode;
      }
      else
      {
        SiteMapNode candidate = null;
        // Retrieve the SiteMapNode that matches the URL.
        lock (this)
        {
          candidate = GetNode(siteMapNodes, rawUrl);
        }
        return candidate;
      }
    }
    // Implement the GetChildNodes method.
    public override SiteMapNodeCollection GetChildNodes(SiteMapNode node)
    {
      SiteMapNodeCollection children = new SiteMapNodeCollection();
      // Iterate through the ArrayList and find all nodes that have the specified node as a parent.
      lock (this)
      {
        for (int i = 0; i < childParentRelationship.Count; i++)
        {

          string nodeUrl = ((DictionaryEntry)childParentRelationship[i]).Key as string;

          SiteMapNode parent = GetNode(childParentRelationship, nodeUrl);

          if (parent != null && node.Url == parent.Url)
          {
            // The SiteMapNode with the Url that corresponds to nodeUrl
            // is a child of the specified node. Get the SiteMapNode for
            // the nodeUrl.
            SiteMapNode child = FindSiteMapNode(nodeUrl);
            if (child != null)
            {
              children.Add(child as SiteMapNode);
            }
            else
            {
              throw new Exception("ArrayLists not in sync.");
            }
          }
        }
      }
      return children;
    }
    protected override SiteMapNode GetRootNodeCore()
    {
      return RootNode;
    }
    // Implement the GetParentNode method.
    public override SiteMapNode GetParentNode(SiteMapNode node)
    {
      // Check the childParentRelationship table and find the parent of the current node.
      // If there is no parent, the current node is the RootNode.
      SiteMapNode parent = null;
      lock (this)
      {
        // Get the Value of the node in childParentRelationship
        parent = GetNode(childParentRelationship, node.Url);
      }
      return parent;
    }

    // Implement the ProviderBase.Initialize property.
    // Initialize is used to initialize the state that the Provider holds, but
    // not actually build the site map.
    public override void Initialize(string name, NameValueCollection attributes)
    {

      lock (this)
      {

        base.Initialize(name, attributes);

        simpleTextProviderName = name;
        sourceFilename = attributes["siteMapFile"];
        siteMapNodes = new ArrayList();
        childParentRelationship = new ArrayList();

        // Build the site map in memory.
        LoadSiteMapFromStore();
      }
    }
    // Private helper methods

    private SiteMapNode GetNode(ArrayList list, string url)
    {
      for (int i = 0; i < list.Count; i++)
      {
        DictionaryEntry item = (DictionaryEntry)list[i];
        if ((string)item.Key == url)
          return item.Value as SiteMapNode;
      }
      return null;
    }

    // Get the URL of the currently displayed page.
    private string FindCurrentUrl()
    {
      try
      {
        // The current HttpContext.
        HttpContext currentContext = HttpContext.Current;
        if (currentContext != null)
        {
          return currentContext.Request.RawUrl;
        }
        else
        {
          throw new Exception("HttpContext.Current is Invalid");
        }
      }
      catch (Exception e)
      {
        throw new NotSupportedException("This provider requires a valid context.",e);
      }
    }
    protected virtual void LoadSiteMapFromStore()
    {
      string pathToOpen;

      lock (this)
      {
        // If a root node exists, LoadSiteMapFromStore has already
        // been called, and the method can return.
        if (rootNode != null)
        {
          return;
        }
        else
        {
          pathToOpen = HttpContext.Current.Server.MapPath("~" + "\\" + sourceFilename);

          if (File.Exists(pathToOpen))
          {
            // Open the file to read from.
            using (StreamReader sr = File.OpenText(pathToOpen))
            {

              // Clear the state of the collections and rootNode
              rootNode = null;
              siteMapNodes.Clear();
              childParentRelationship.Clear();

              // Parse the file and build the site map
              string s = "";
              string[] nodeValues = null;
              SiteMapNode temp = null;

              while ((s = sr.ReadLine()) != null)
              {

                // Build the various SiteMapNode objects and add
                // them to the ArrayList collections. The format used
                // is: URL,TITLE,DESCRIPTION,PARENTURL

                nodeValues = s.Split(',');

                temp = new SiteMapNode(this,
                    HttpRuntime.AppDomainAppVirtualPath + "/" + nodeValues[0],
                    HttpRuntime.AppDomainAppVirtualPath + "/" + nodeValues[0],
                    nodeValues[1],
                    nodeValues[2]);

                // Is this a root node yet?
                if (null == rootNode &&
                    (null == nodeValues[3] || nodeValues[3] == String.Empty))
                {
                  rootNode = temp;
                }

              // If not the root node, add the node to the various collections.
                else
                {
                  siteMapNodes.Add(new DictionaryEntry(temp.Url, temp));
                  // The parent node has already been added to the collection.
                  SiteMapNode parentNode =
                           FindSiteMapNode(HttpRuntime.AppDomainAppVirtualPath + "/" + nodeValues[3]);
                  if (parentNode != null)
                  {
                    childParentRelationship.Add(new DictionaryEntry(temp.Url, parentNode));
                  }
                  else
                  {
                    throw new Exception("Parent node not found for current node.");
                  }
                }
              }
            }
          }
          else
          {
            throw new Exception("File not found");
          }
        }
      }
      return;
    }
  }

}

.NET Framework
Available since 2.0

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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