SiteMapProvider Klasse

Definition

public ref class SiteMapProvider abstract : System::Configuration::Provider::ProviderBase

public abstract class SiteMapProvider : System.Configuration.Provider.ProviderBase

type SiteMapProvider = class
    inherit ProviderBase

Public MustInherit Class SiteMapProvider
Inherits ProviderBase

Vererbung

Object

ProviderBase

SiteMapProvider

Abgeleitet

System.Web.StaticSiteMapProvider

Beispiele

Im folgenden Codebeispiel wird veranschaulicht, wie eine Klasse geschrieben wird, die die abstrakte SiteMapProvider Klasse implementiert. Dieses Beispiel enthält nur ein Beispiel SiteMapProvider und eine Beispieltextdatei, die damit funktioniert. Zum Ausführen des Beispiels benötigen Sie auch einen Eintrag in der Web.config-Datei und eine ASPX-Seite. Diese finden Sie in der Dokumentation für die SiteMapDataSource.SiteMapProvider Eigenschaft.

Im Beispiel wird eine durch Trennzeichen getrennte Datei verwendet, die einer erwarteten Struktur zum Laden von Sitemap-Informationen folgt. Die erste Zeile der Datei stellt den Stammknoten der Sitemap dar, und nachfolgende Zeilen sind Unterknoten. Jeder Unterknoten identifiziert seinen übergeordneten Knoten anhand der URL. Ein Beispiel für eine Datei, die diese Kriterien erfüllt, ist unten dargestellt.

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  

Die SimpleTextSiteMapProvider stellt Beispielimplementierungen aller SiteMapProvider Eigenschaften und Methoden bereit.

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

Hinweise

Die StaticSiteMapProvider Klassen und XmlSiteMapProvider stellen die Standardimplementierungen der abstrakten SiteMapProvider Klasse dar. Die XmlSiteMapProvider verwendet eine XML-Datei mit dem Namen Web.sitemap zum Speichern von Siteübersichtsdaten. Weitere Informationen zur Datei Web.sitemap finden Sie unter ASP.NET Site Maps.

Die SiteMapProvider -Klasse unterstützt das Konzept einer Siteübersichtsanbieterhierarchie, indem die RootProvider Eigenschaften und ParentProvider deklariert werden. Ein SiteMapProvider kann ein untergeordnetes oder übergeordnetes Element eines anderen Anbieters sein. Dies ermöglicht Szenarien, in denen verschiedene Inhaltsbereiche einer Website im Besitz verschiedener Entwicklungsgruppen sind oder von diesen implementiert werden, die ihre eigenen Websitekarten und Siteübersichtsanbieter verwalten.

Alle SiteMapProvider Objekte werden in den Web.config-Dateien konfiguriert. Alle Siteübersichtsanbieter, die in diesen Konfigurationsdateien deklariert sind, werden zur Laufzeit geladen und zum Laden und Verarbeiten von Websitenavigationsdaten verwendet. Das SiteMap -Objekt, das alle Anbieter nachverfolgt, die über seine Providers Eigenschaftssammlung verfügbar sind, bietet programmgesteuerten Zugriff auf die Navigationsdaten, die von den Anbietern verwaltet werden. Im folgenden Codebeispiel wird das Format veranschaulicht, das zum Deklarieren eines Siteübersichtsanbieters in einer Web.config-Datei verwendet wird.

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

Die Websitenavigationsdaten, die von diesen Anbietern geladen werden, werden von anderen Komponenten der Websiteübersichtsinfrastruktur verwendet, z. B. von den SiteMapPath Steuerelementen und TreeView , um Siteübersichtsinformationen für Benutzer anzuzeigen.

Wenn Sie Einen eigenen Siteübersichtsanbieter implementieren, können Sie die Quelldatei im App_Code Verzeichnis Ihrer ASP.NET-Anwendung platzieren, und die Assembly wird dann automatisch kompiliert. Sie können auch Ihren eigenen Siteübersichtsanbieter im globalen Assemblycache (GAC) platzieren und einen vollqualifizierten Verweis darauf in der Web.config-Datei bereitstellen. Weitere Informationen zu Compilerdiensten finden Sie unter Arbeiten mit Assemblys und dem globalen Assemblycache.

Hinweise für Ausführende

Wenn Sie von der SiteMapProvider -Klasse erben, müssen Sie die folgenden Member überschreiben: GetRootNodeCore(), FindSiteMapNode(String), GetChildNodes(SiteMapNode)und GetParentNode(SiteMapNode).

Konstruktoren

Eigenschaften

Methoden

Ereignisse

Gilt für:

Weitere Informationen

• SiteMapProvider
• XmlSiteMapProvider
• Übersicht über die ASP.NET-Websitenavigation
• ASP.NET Site Maps
• ASP.NET Websitenavigationsanbieter
• Schützen ASP.NET Websitenavigation
• Arbeiten mit Assemblys und dem globalen Assemblychache