SiteMapProvider Class
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
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.
public ref class SiteMapProvider abstract : System::Configuration::Provider::ProviderBasepublic abstract class SiteMapProvider : System.Configuration.Provider.ProviderBasetype SiteMapProvider = class
inherit ProviderBasePublic MustInherit Class SiteMapProvider
Inherits ProviderBase- Inheritance
- Derived
Examples
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 &&
string.IsNullOrEmpty(nodeValues[3]))
{
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;
}
}
}
Imports System.Collections
Imports System.Collections.Specialized
Imports System.Configuration.Provider
Imports System.IO
Imports System.Security.Permissions
Imports System.Web
Namespace Samples.AspNet.VB
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public Class SimpleTextSiteMapProvider
Inherits SiteMapProvider
Private parentSiteMapProvider As SiteMapProvider = Nothing
Private simpleTextProviderName As String = Nothing
Private sourceFilename As String = Nothing
Private aRootNode As SiteMapNode = Nothing
Private siteMapNodes As ArrayList = Nothing
Private childParentRelationship As ArrayList = Nothing
' A default constructor. The Name property is initialized in the
' Initialize method.
Public Sub New()
End Sub
' Implement the CurrentNode property.
Public Overrides ReadOnly Property CurrentNode() As SiteMapNode
Get
Dim currentUrl As String = FindCurrentUrl()
' Find the SiteMapNode that represents the current page.
Dim aCurrentNode As SiteMapNode = FindSiteMapNode(currentUrl)
Return aCurrentNode
End Get
End Property
' Implement the RootNode property.
Public Overrides ReadOnly Property RootNode() As SiteMapNode
Get
Return aRootNode
End Get
End Property
' Implement the ParentProvider property.
Public Overrides Property ParentProvider() As SiteMapProvider
Get
Return parentSiteMapProvider
End Get
Set(ByVal value As SiteMapProvider)
parentSiteMapProvider = Value
End Set
End Property
' Implement the RootProvider property.
Public Overrides ReadOnly Property RootProvider() As SiteMapProvider
Get
' If the current instance belongs to a provider hierarchy, it
' cannot be the RootProvider. Rely on the ParentProvider.
If Not (Me.ParentProvider Is Nothing) Then
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 Me
End If
End Get
End Property
' Implement the FindSiteMapNode method.
Public Overrides Function FindSiteMapNode(ByVal rawUrl As String) As SiteMapNode
' Does the root node match the URL?
If RootNode.Url = rawUrl Then
Return RootNode
Else
Dim candidate As SiteMapNode = Nothing
' Retrieve the SiteMapNode that matches the URL.
SyncLock Me
candidate = GetNode(siteMapNodes, rawUrl)
End SyncLock
Return candidate
End If
End Function 'FindSiteMapNode
' Implement the GetChildNodes method.
Public Overrides Function GetChildNodes(ByVal node As SiteMapNode) As SiteMapNodeCollection
Dim children As New SiteMapNodeCollection()
' Iterate through the ArrayList and find all nodes that have the specified node as a parent.
SyncLock Me
Dim i As Integer
For i = 0 To childParentRelationship.Count - 1
Dim de As DictionaryEntry = CType(childParentRelationship(i), DictionaryEntry)
Dim nodeUrl As String = CType(de.Key, String)
Dim parent As SiteMapNode = GetNode(childParentRelationship, nodeUrl)
If Not (parent Is Nothing) AndAlso node.Url = parent.Url Then
' The SiteMapNode with the Url that corresponds to nodeUrl
' is a child of the specified node. Get the SiteMapNode for
' the nodeUrl.
Dim child As SiteMapNode = FindSiteMapNode(nodeUrl)
If Not (child Is Nothing) Then
children.Add(CType(child, SiteMapNode))
Else
Throw New Exception("ArrayLists not in sync.")
End If
End If
Next i
End SyncLock
Return children
End Function 'GetChildNodes
Protected Overrides Function GetRootNodeCore() As SiteMapNode
Return RootNode
End Function ' GetRootNodeCore()
' Implement the GetParentNode method.
Public Overrides Function GetParentNode(ByVal node As SiteMapNode) As SiteMapNode
' Check the childParentRelationship table and find the parent of the current node.
' If there is no parent, the current node is the RootNode.
Dim parent As SiteMapNode = Nothing
SyncLock Me
' Get the Value of the node in childParentRelationship
parent = GetNode(childParentRelationship, node.Url)
End SyncLock
Return parent
End Function 'GetParentNode
' Implement the ProviderBase.Initialize method.
' Initialize is used to initialize the state that the Provider holds, but
' not actually build the site map.
Public Overrides Sub Initialize(ByVal name As String, ByVal attributes As NameValueCollection)
SyncLock Me
MyBase.Initialize(name, attributes)
simpleTextProviderName = name
sourceFilename = attributes("siteMapFile")
siteMapNodes = New ArrayList()
childParentRelationship = New ArrayList()
' Build the site map in memory.
LoadSiteMapFromStore()
End SyncLock
End Sub
' Private helper methods
Private Function GetNode(ByVal list As ArrayList, ByVal url As String) As SiteMapNode
Dim i As Integer
For i = 0 To list.Count - 1
Dim item As DictionaryEntry = CType(list(i), DictionaryEntry)
If CStr(item.Key) = url Then
Return CType(item.Value, SiteMapNode)
End If
Next i
Return Nothing
End Function 'GetNode
' Get the URL of the currently displayed page.
Private Function FindCurrentUrl() As String
Try
' The current HttpContext.
Dim currentContext As HttpContext = HttpContext.Current
If Not (currentContext Is Nothing) Then
Return currentContext.Request.RawUrl
Else
Throw New Exception("HttpContext.Current is Invalid")
End If
Catch e As Exception
Throw New NotSupportedException("This provider requires a valid context.", e)
End Try
End Function 'FindCurrentUrl
Protected Overridable Sub LoadSiteMapFromStore()
Dim pathToOpen As String
SyncLock Me
' If a root node exists, LoadSiteMapFromStore has already
' been called, and the method can return.
If Not (aRootNode Is Nothing) Then
Return
Else
pathToOpen = HttpContext.Current.Server.MapPath("~" & "\\" & sourceFilename)
If File.Exists(pathToOpen) Then
' Open the file to read from.
Dim sr As StreamReader = File.OpenText(pathToOpen)
Try
' Clear the state of the collections and aRootNode
aRootNode = Nothing
siteMapNodes.Clear()
childParentRelationship.Clear()
' Parse the file and build the site map
Dim s As String = ""
Dim nodeValues As String() = Nothing
Dim temp As SiteMapNode = Nothing
Do
s = sr.ReadLine()
If Not s Is Nothing Then
' Build the various SiteMapNode objects and add
' them to the ArrayList collections. The format used
' is: URL,TITLE,DESCRIPTION,PARENTURL
nodeValues = s.Split(","c)
temp = New SiteMapNode(Me, _
HttpRuntime.AppDomainAppVirtualPath & "/" & nodeValues(0), _
HttpRuntime.AppDomainAppVirtualPath & "/" & nodeValues(0), _
nodeValues(1), _
nodeValues(2))
' Is this a root node yet?
If aRootNode Is Nothing AndAlso _
(nodeValues(3) Is Nothing OrElse _
nodeValues(3) = String.Empty) Then
aRootNode = 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.
Dim parentNode As SiteMapNode = _
FindSiteMapNode(HttpRuntime.AppDomainAppVirtualPath & "/" & nodeValues(3))
If Not (parentNode Is Nothing) Then
childParentRelationship.Add(New DictionaryEntry(temp.Url, parentNode))
Else
Throw New Exception("Parent node not found for current node.")
End If
End If
End If
Loop Until s Is Nothing
Finally
sr.Close()
End Try
Else
Throw New Exception("File not found")
End If
End If
End SyncLock
Return
End Sub
End Class
End Namespace
Remarks
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 Implementers
When you inherit from the SiteMapProvider class, you must override the following members: GetRootNodeCore(), FindSiteMapNode(String), GetChildNodes(SiteMapNode), and GetParentNode(SiteMapNode).
Constructors
| SiteMapProvider() |
Initializes a new instance of the SiteMapProvider class. |
Properties
| CurrentNode |
Gets the SiteMapNode object that represents the currently requested page. |
| Description |
Gets a brief, friendly description suitable for display in administrative tools or other user interfaces (UIs). (Inherited from ProviderBase) |
| EnableLocalization |
Gets or sets a Boolean value indicating whether localized values of SiteMapNode attributes are returned. |
| Name |
Gets the friendly name used to refer to the provider during configuration. (Inherited from ProviderBase) |
| ParentProvider |
Gets or sets the parent SiteMapProvider object of the current provider. |
| ResourceKey |
Get or sets the resource key that is used for localizing SiteMapNode attributes. |
| RootNode |
Gets the root SiteMapNode object of the site map data that the current provider represents. |
| RootProvider |
Gets the root SiteMapProvider object in the current provider hierarchy. |
| SecurityTrimmingEnabled |
Gets a Boolean value indicating whether a site map provider filters site map nodes based on a user's role. |
Methods
| AddNode(SiteMapNode, SiteMapNode) |
Adds a SiteMapNode object to the node collection that is maintained by the site map provider and specifies the parent SiteMapNode object. |
| AddNode(SiteMapNode) |
Adds a SiteMapNode object to the node collection that is maintained by the site map provider. |
| Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
| FindSiteMapNode(HttpContext) |
Retrieves a SiteMapNode object that represents the currently requested page using the specified HttpContext object. |
| FindSiteMapNode(String) |
When overridden in a derived class, retrieves a SiteMapNode object that represents the page at the specified URL. |
| FindSiteMapNodeFromKey(String) |
Retrieves a SiteMapNode object based on a specified key. |
| GetChildNodes(SiteMapNode) |
When overridden in a derived class, retrieves the child nodes of a specific SiteMapNode. |
| GetCurrentNodeAndHintAncestorNodes(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. |
| GetCurrentNodeAndHintNeighborhoodNodes(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. |
| GetHashCode() |
Serves as the default hash function. (Inherited from Object) |
| GetParentNode(SiteMapNode) |
When overridden in a derived class, retrieves the parent node of a specific SiteMapNode object. |
| GetParentNodeRelativeToCurrentNodeAndHintDownFromParent(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. |
| GetParentNodeRelativeToNodeAndHintDownFromParent(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. |
| GetRootNodeCore() |
When overridden in a derived class, retrieves the root node of all the nodes that are currently managed by the current provider. |
| GetRootNodeCoreFromProvider(SiteMapProvider) |
Retrieves the root node of all the nodes that are currently managed by the specified site map provider. |
| GetType() |
Gets the Type of the current instance. (Inherited from Object) |
| HintAncestorNodes(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. |
| HintNeighborhoodNodes(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. |
| Initialize(String, NameValueCollection) |
Initializes the SiteMapProvider implementation, including any resources that are needed to load site map data from persistent storage. |
| IsAccessibleToUser(HttpContext, SiteMapNode) |
Retrieves a Boolean value indicating whether the specified SiteMapNode object can be viewed by the user in the specified context. |
| MemberwiseClone() |
Creates a shallow copy of the current Object. (Inherited from Object) |
| RemoveNode(SiteMapNode) |
Removes the specified SiteMapNode object from the node collection that is maintained by the site map provider. |
| ResolveSiteMapNode(HttpContext) |
Raises the SiteMapResolve event. |
| ToString() |
Returns a string that represents the current object. (Inherited from Object) |
Events
| SiteMapResolve |
Occurs when the CurrentNode property is called. |
