Ejemplo de proveedor de mapas de sitio de Microsoft Access

Actualización: noviembre 2007

Ilustra un proveedor completo de mapas de sitio basado en Microsoft Access.

Ejemplo

Descripción

El siguiente ejemplo de código muestra cómo puede ampliarse la clase StaticSiteMapProvider para que utilice Microsoft Access como proveedor de mapas de sitio. El proveedor de mapas de sitio utiliza el proveedor de datos de .NET Framework para OLE DB para conectarse a la base de datos de Microsoft Access.

Código

Imports System
Imports System.Collections
Imports System.Collections.Specialized
Imports System.Data
Imports System.Data.OleDb
Imports System.Security.Permissions
Imports System.Web

Namespace Samples.AspNet.VB.Controls

    ' An extremely simple AccessSiteMapProvider that only supports a
    ' site map node hierarchy one level deep.
    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public Class AccessSiteMapProvider
        Inherits StaticSiteMapProvider

        Private aRootNode As SiteMapNode = Nothing
        Private accessConnection As OleDbConnection = Nothing

        ' This string is case sensitive.
        Private AccessConnectionStringName As String = "accessSiteMapConnectionString"

        ' Implement a default constructor.
        Public Sub New()
        End Sub 'New

        ' Some basic state to help track the initialization state of the provider.
        Private initialized As Boolean = False

        Public Overridable ReadOnly Property IsInitialized() As Boolean
            Get
                Return initialized
            End Get
        End Property

        ' Return the root node of the current site map.
        Public Overrides ReadOnly Property RootNode() As SiteMapNode
            Get
                Return BuildSiteMap()
            End Get
        End Property

        Protected Overrides Function GetRootNodeCore() As SiteMapNode
            Return RootNode
        End Function

        ' Initialize is used to initialize the properties and any state that the
        ' AccessProvider holds, but is not used to build the site map.
        ' The site map is built when the BuildSiteMap method is called.
        Public Overrides Sub Initialize(ByVal name As String, ByVal attributes As NameValueCollection)
            If IsInitialized Then
                Return
            End If
            MyBase.Initialize(name, attributes)

            ' Create and test the connection to the Microsoft Access database.
            ' Retrieve the Value of the Access connection string from the
            ' attributes NameValueCollection.
            Dim connectionString As String = attributes(AccessConnectionStringName)

            If Nothing = connectionString OrElse connectionString.Length = 0 Then
                Throw New Exception("The connection string was not found.")
            Else
                accessConnection = New OleDbConnection(connectionString)
            End If
            initialized = True
        End Sub 'Initialize

        ' SiteMapProvider and StaticSiteMapProvider methods that this derived class must override.
        '
        ' Clean up any collections or other state that an instance of this may hold.
        Protected Overrides Sub Clear()
            SyncLock Me
                aRootNode = Nothing
                MyBase.Clear()
            End SyncLock
        End Sub 'Clear

        ' Build an in-memory representation from persistent
        ' storage, and return the root node of the site map.
        Public Overrides Function BuildSiteMap() As SiteMapNode

            ' Since the SiteMap class is static, make sure that it is
            ' not modified while the site map is built.
            SyncLock Me

                ' If there is no initialization, this method is being
                ' called out of order.
                If Not IsInitialized Then
                    Throw New Exception("BuildSiteMap called incorrectly.")
                End If

                ' If there is no root node, then there is no site map.
                If aRootNode Is Nothing Then
                    ' Start with a clean slate
                    Clear()

                    ' Select the root node of the site map from Microsoft Access.
                    Dim rootNodeId As Integer = -1

                    If accessConnection.State = ConnectionState.Closed Then
                        accessConnection.Open()
                    End If
                    Dim rootNodeCommand As New OleDbCommand("SELECT nodeid, url, name FROM SiteMap WHERE parentnodeid IS NULL", accessConnection)
                    Dim rootNodeReader As OleDbDataReader = rootNodeCommand.ExecuteReader()

                    If rootNodeReader.HasRows Then
                        rootNodeReader.Read()
                        rootNodeId = rootNodeReader.GetInt32(0)
                        ' Create a SiteMapNode that references the current StaticSiteMapProvider.
                        aRootNode = New SiteMapNode(Me, rootNodeId.ToString(), rootNodeReader.GetString(1), rootNodeReader.GetString(2))
                    Else
                        Return Nothing
                    End If
                    rootNodeReader.Close()
                    ' Select the child nodes of the root node.
                    Dim childNodesCommand As New OleDbCommand("SELECT nodeid, url, name FROM SiteMap WHERE parentnodeid = ?", accessConnection)
                    Dim rootParam As New OleDbParameter("parentid", OleDbType.Integer)
                    rootParam.Value = rootNodeId
                    childNodesCommand.Parameters.Add(rootParam)

                    Dim childNodesReader As OleDbDataReader = childNodesCommand.ExecuteReader()

                    If childNodesReader.HasRows Then

                        Dim childNode As SiteMapNode = Nothing
                        While childNodesReader.Read()
                            childNode = New SiteMapNode(Me, _
                            childNodesReader.GetInt32(0).ToString(), _
                            childNodesReader.GetString(1), _
                            childNodesReader.GetString(2))

                            ' Use the SiteMapNode AddNode method to add
                            ' the SiteMapNode to the ChildNodes collection.
                            AddNode(childNode, aRootNode)
                        End While
                    End If

                    childNodesReader.Close()
                    accessConnection.Close()
                End If
                Return aRootNode
            End SyncLock

        End Function 'BuildSiteMap

    End Class 'AccessSiteMapProvider

End Namespace

namespace Samples.AspNet.CS.Controls {

    using System;
    using System.Collections;
    using System.Collections.Specialized;
    using System.Data;
    using System.Data.OleDb;
    using System.Security.Permissions;
    using System.Web;

    /// An extremely simple AccessSiteMapProvider that only supports a
    /// site map node hierarchy 1 level deep.
    [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
    public class AccessSiteMapProvider : StaticSiteMapProvider
    {
        private SiteMapNode rootNode =  null;
        private OleDbConnection accessConnection = null;

        // This string is case sensitive.
        private string AccessConnectionStringName = "accessSiteMapConnectionString";

        // Implement a default constructor.
        public AccessSiteMapProvider () { }

        // Some basic state to help track the initialization state of the provider.
        private bool initialized = false;
        public virtual bool IsInitialized {
            get {
                return initialized;
            }
        }
        // Return the root node of the current site map.
        public override SiteMapNode RootNode {
            get {
                SiteMapNode temp = null;
                temp = BuildSiteMap();
                return temp;
            }
        }
        protected override SiteMapNode GetRootNodeCore() {
            return RootNode;
        }
        // Initialize is used to initialize the properties and any state that the
        // AccessProvider holds, but is not used to build the site map.
        // The site map is built when the BuildSiteMap method is called.
        public override void Initialize(string name, NameValueCollection attributes) {
            if (IsInitialized)
                return;

            base.Initialize(name, attributes);

            // Create and test the connection to the Microsoft Access database.

            // Retrieve the Value of the Access connection string from the
            // attributes NameValueCollection.
            string connectionString = attributes[AccessConnectionStringName];

            if (null == connectionString || connectionString.Length == 0)
                throw new Exception ("The connection string was not found.");
            else
                accessConnection = new OleDbConnection(connectionString);

            initialized = true;
        }

        ///
        /// SiteMapProvider and StaticSiteMapProvider methods that this derived class must override.
        ///
        // Clean up any collections or other state that an instance of this may hold.
        protected override void Clear() {
            lock (this) {
                rootNode = null;
                base.Clear();
            }
        }

        // Build an in-memory representation from persistent
        // storage, and return the root node of the site map.
        public override SiteMapNode BuildSiteMap() {

            // Since the SiteMap class is static, make sure that it is
            // not modified while the site map is built.
            lock(this) {

                // If there is no initialization, this method is being
                // called out of order.
                if (! IsInitialized) {
                    throw new Exception("BuildSiteMap called incorrectly.");
                }

                // If there is no root node, then there is no site map.
                if (null == rootNode) {
                    // Start with a clean slate
                    Clear();

                    // Select the root node of the site map from Microsoft Access.
                    int rootNodeId = -1;

                    if (accessConnection.State == ConnectionState.Closed)
                        accessConnection.Open();
                    OleDbCommand rootNodeCommand =
                        new OleDbCommand("SELECT nodeid, url, name FROM SiteMap WHERE parentnodeid IS NULL",
                                         accessConnection);
                    OleDbDataReader rootNodeReader = rootNodeCommand.ExecuteReader();

                    if(rootNodeReader.HasRows) {
                        rootNodeReader.Read();
                        rootNodeId = rootNodeReader.GetInt32(0);
                        // Create a SiteMapNode that references the current StaticSiteMapProvider.
                        rootNode   = new SiteMapNode(this,
                                                     rootNodeId.ToString(),
                                                     rootNodeReader.GetString(1),
                                                     rootNodeReader.GetString(2));

                    }
                    else return null;

                    rootNodeReader.Close();
                    // Select the child nodes of the root node.
                    OleDbCommand childNodesCommand =
                        new OleDbCommand("SELECT nodeid, url, name FROM SiteMap WHERE parentnodeid = ?",
                                         accessConnection);
                    OleDbParameter rootParam = new OleDbParameter("parentid", OleDbType.Integer);
                    rootParam.Value = rootNodeId;
                    childNodesCommand.Parameters.Add(rootParam);

                    OleDbDataReader childNodesReader = childNodesCommand.ExecuteReader();

                    if (childNodesReader.HasRows) {

                        SiteMapNode childNode = null;
                        while(childNodesReader.Read()) {
                            childNode =  new SiteMapNode(this,
                                                         childNodesReader.GetInt32(0).ToString(),
                                                         childNodesReader.GetString(1),
                                                         childNodesReader.GetString(2));

                            // Use the SiteMapNode AddNode method to add
                            // the SiteMapNode to the ChildNodes collection.
                            AddNode(childNode, rootNode);
                        }
                    }

                    childNodesReader.Close();
                    accessConnection.Close();
                }
                return rootNode;
            }
        }
    }
}

#using <System.Data.dll>
#using <System.Transactions.dll>
#using <System.EnterpriseServices.dll>
#using <System.dll>
#using <System.Web.dll>
#using <System.Configuration.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
using namespace System::Configuration;
using namespace System::Data;
using namespace System::Data::OleDb;
using namespace System::Security::Permissions;
using namespace System::Web;

/// An extremely simple AccessSiteMapProvider that only supports a
/// site map node hierarchy 1 level deep.

[AspNetHostingPermission(SecurityAction::Demand,Level=AspNetHostingPermissionLevel::Minimal)]
public ref class AccessSiteMapProvider: public StaticSiteMapProvider
{
private:
   SiteMapNode ^ rootNode;
   OleDbConnection^ accessConnection;

   // This string is case sensitive.
   String^ AccessConnectionStringName;

public:
   // Implement a default constructor.
   AccessSiteMapProvider()
   {
      initialized = false;
      AccessConnectionStringName = "accessSiteMapConnectionString";
   }


private:

   // Some basic state to help track the initialization state of the provider.
   bool initialized;

public:

   property bool IsInitialized 
   {
      virtual bool get()
      {
         return initialized;
      }

   }

   property SiteMapNode ^ RootNode 
   {

      // Return the root node of the current site map.
      virtual SiteMapNode ^ get() override
      {
         SiteMapNode ^ temp = nullptr;
         temp = BuildSiteMap();
         return temp;
      }

   }

protected:

   virtual SiteMapNode ^ GetRootNodeCore() override
   {
      return RootNode;
   }


public:

   // Initialize is used to initialize the properties and any state that the
   // AccessProvider holds, but is not used to build the site map.
   // The site map is built when the BuildSiteMap method is called.
   virtual void Initialize( String^ name, NameValueCollection^ attributes ) override
   {
      if ( IsInitialized )
            return;

      StaticSiteMapProvider::Initialize( name, attributes );

      // Create and test the connection to the Microsoft Access database.
      // Retrieve the Value of the Access connection string from the
      // attributes NameValueCollection.
      String^ connectionString = attributes[ AccessConnectionStringName ];
      if ( nullptr == connectionString || connectionString->Length == 0 )
            throw gcnew Exception( "The connection string was not found." );
      else
            accessConnection = gcnew OleDbConnection( connectionString );

      initialized = true;
   }


protected:

   ///
   /// SiteMapProvider and StaticSiteMapProvider methods that this derived class must override.
   ///
   // Clean up any collections or other state that an instance of this may hold.
   virtual void Clear() override
   {
      System::Threading::Monitor::Enter( this );
      try
      {
         rootNode = nullptr;
         StaticSiteMapProvider::Clear();
      }
      finally
      {
         System::Threading::Monitor::Exit( this );
      }

   }


public:

   // Build an in-memory representation from persistent
   // storage, and return the root node of the site map.
   virtual SiteMapNode ^ BuildSiteMap() override
   {
      // Since the SiteMap class is static, make sure that it is
      // not modified while the site map is built.
      System::Threading::Monitor::Enter( this );
      try
      {

         // If there is no initialization, this method is being
         // called out of order.
         if (  !IsInitialized )
         {
            throw gcnew Exception( "BuildSiteMap called incorrectly." );
         }

         // If there is no root node, then there is no site map.
         if ( nullptr == rootNode )
         {

            // Start with a clean slate
            Clear();

            // Select the root node of the site map from Microsoft Access.
            int rootNodeId = -1;
            if ( accessConnection->State == ConnectionState::Closed )
               accessConnection->Open();

            OleDbCommand^ rootNodeCommand = gcnew OleDbCommand
               ("SELECT nodeid, url, name FROM SiteMap WHERE parentnodeid IS NULL", accessConnection);
            OleDbDataReader^ rootNodeReader = rootNodeCommand->ExecuteReader();
            if ( rootNodeReader->HasRows )
            {
               rootNodeReader->Read();
               rootNodeId = rootNodeReader->GetInt32( 0 );

               // Create a SiteMapNode that references the current StaticSiteMapProvider.
               rootNode = gcnew SiteMapNode(this, rootNodeId.ToString(), 
                  rootNodeReader->GetString( 1 ),rootNodeReader->GetString( 2 ));
            }
            else
               return nullptr;
            rootNodeReader->Close();

            // Select the child nodes of the root node.
            OleDbCommand^ childNodesCommand = gcnew OleDbCommand
               ("SELECT nodeid, url, name FROM SiteMap WHERE parentnodeid = ?", accessConnection);
            OleDbParameter^ rootParam = gcnew OleDbParameter( "parentid", OleDbType::Integer);
            rootParam->Value = rootNodeId;
            childNodesCommand->Parameters->Add( rootParam );
            OleDbDataReader^ childNodesReader = childNodesCommand->ExecuteReader();
            if ( childNodesReader->HasRows )
            {
               SiteMapNode ^ childNode = nullptr;
               while ( childNodesReader->Read() )
               {
                  childNode = gcnew SiteMapNode( this, 
                      System::Convert::ToString(childNodesReader->GetInt32( 0 )),
                     childNodesReader->GetString( 1 ),
                     childNodesReader->GetString( 2 ) 
                  );
                  // Use the SiteMapNode AddNode method to add
                  // the SiteMapNode to the ChildNodes collection.
                  AddNode( childNode, rootNode );
               }
            }
            childNodesReader->Close();
            accessConnection->Close();
         }
         return rootNode;
      }
      finally
      {
         System::Threading::Monitor::Exit( this );
      }

   }

};

package Samples.AspNet.JSL;
import System.*;
import System.Collections.*;
import System.Collections.Specialized.*;
import System.Data.*;
import System.Data.OleDb.*;
import System.Web.*;
import System.Configuration.*;

/// An extremely simple AccessSiteMapProvider that only supports a
/// site map node hierarchy 1 level deep.
public class AccessSiteMapProvider extends StaticSiteMapProvider
{
    private SiteMapNode rootNode = null;
    private OleDbConnection accessConnection = null;

    // This string is case sensitive.
    public String accessConnectionStringName = "accessSiteMapConnectionString";

    // Implement a default constructor.
    public AccessSiteMapProvider()
    {
    } //AccessSiteMapProvider 

    // Some basic state to help track the initialization state of the provider.
    private boolean initialized = false;

    /** @property 
     */
    public boolean get_IsInitialized()
    {
        return initialized;
    } //get_IsInitized.

    // Return the root node of the current site map.
    /** @property 
     */
    public SiteMapNode get_RootNode() throws Exception
    {
        SiteMapNode temp = null;
        temp = BuildSiteMap();
        return temp;
    } //get_RootNode

    // Initialize is used to initialize the properties and any state that the
    // AccessProvider holds, but is not used to build the site map.
    // The site map is built when the BuildSiteMap method is called.
    public void Initialize(String name, NameValueCollection attributes) 
        throws Exception
    {
        if (get_IsInitialized())
        {
            return;
        }

        super.Initialize(name, attributes);
        // Create and test the connection to the Microsoft Access database.
        // Retrieve the Value of the Access connection string from the
        // attributes NameValueCollection.
        String connectionString = attributes.get_Item(
            accessConnectionStringName);

        if (null == connectionString || connectionString.get_Length() == 0)
        {
            throw new Exception("The connection string was not found.");
        }
        else
        {
            accessConnection = new OleDbConnection(connectionString);
        }
        initialized = true;
    } //Initialize

    ///
    /// SiteMapProvider and StaticSiteMapProvider methods that this 
    /// derived class must override.
    ///
    // Clean up any collections or other state that an instance of this may hold.
    protected void Clear()
    {
        synchronized (this)
        {
            rootNode = null;
            super.Clear();
        }
    } //Clear

    // Build an in-memory representation from persistent
    // storage, and return the root node of the site map.
    public SiteMapNode BuildSiteMap() throws Exception
    {
        // Since the SiteMap class is static, make sure that it is
        // not modified while the site map is built.
        synchronized (this)
        {
            // If there is no initialization, this method is being
            // called out of order.
            if (!get_IsInitialized())
            {
                throw new Exception("BuildSiteMap called incorrectly.");
            }
            // If there is no root node, then there is no site map.
            if (null == rootNode)
            {
                // Start with a clean slate
                Clear();
                // Select the root node of the site map from Microsoft Access.
                int rootNodeId = -1;

                if (accessConnection.get_State().Equals(ConnectionState.Closed))
                {
                    accessConnection.Open();
                }

                OleDbCommand rootNodeCommand = new OleDbCommand(
                    "SELECT nodeid, url, name FROM SiteMap WHERE "
                    + "parentnodeid IS NULL", accessConnection);
                OleDbDataReader rootNodeReader = rootNodeCommand.ExecuteReader();

                if (rootNodeReader.get_HasRows())
                {
                    rootNodeReader.Read();
                    rootNodeId = rootNodeReader.GetInt32(0);
                    // Create a SiteMapNode that references the current 
                    // StaticSiteMapProvider.
                    rootNode = new SiteMapNode(this,
                        ((Int32)rootNodeId).ToString(), rootNodeReader.
                        GetString(1), rootNodeReader.GetString(2));
                }
                else
                {
                    return null;
                }
                rootNodeReader.Close();
                // Select the child nodes of the root node.
                OleDbCommand childNodesCommand = new OleDbCommand(
                    "SELECT nodeid, url, name FROM SiteMap WHERE "
                    + "parentnodeid = ?", accessConnection);
                OleDbParameter rootParam = new OleDbParameter("parentid",
                    OleDbType.Integer);
                rootParam.set_Value((Int32)rootNodeId);
                childNodesCommand.get_Parameters().Add(rootParam);

                OleDbDataReader childNodesReader = childNodesCommand.
                    ExecuteReader();

                if (childNodesReader.get_HasRows())
                {
                    SiteMapNode childNode = null;
                    while (childNodesReader.Read())
                    {
                        childNode = new SiteMapNode(this,
                            Convert.ToString(childNodesReader.GetInt32(0)), 
                            childNodesReader.GetString(1),
                            childNodesReader.GetString(2));
                        // Use the SiteMapNode AddNode method to add
                        // the SiteMapNode to the ChildNodes collection.
                        AddNode(childNode, rootNode);
                    }
                }

                childNodesReader.Close();
                accessConnection.Close();
            }
            return rootNode;
        }
    } //BuildSiteMap

    protected SiteMapNode GetRootNodeCore()
    {
        return null;
    } //GetRootNodeCore
} //AccessSiteMapProvider 

Comentarios

Para crear la tabla de Microsoft Access que se utiliza en el ejemplo de código anterior como almacén de datos del mapa del sitio, emita la siguiente consulta de definición de datos en una nueva base de datos de Microsoft Access o en una existente y, a continuación, guarde la base de datos de Microsoft Access con el nombre de archivo Sitemap.mbd.

CREATE TABLE SiteMap
(
  URL Text (255) UNIQUE,
  NAME Text (255) NOT NULL,
  PARENTNODEID Int32,
    CONSTRAINT NODEID PRIMARY KEY (URL, NAME)
)

Rellene la tabla con los siguientes tipos de datos, y muestre los archivos que tiene en el sitio Web o los archivos que puede crear. En la tabla siguiente aparece una lista de archivos de ejemplo.

Nota:

Como los orígenes de datos contienen sintaxis diferentes de SQL, algunos comandos funcionarán con un origen de datos, pero no con otro. Por tanto, se recomienda que cree un proveedor de mapas de sitio específico para su origen de datos, aun cuando esté utilizando el proveedor de datos de .NET Framework para ODBC o el proveedor de datos de .NET Framework para OLE DB para tener acceso al origen de datos (por ejemplo, SybaseSiteMapProvider, OracleSiteMapProvider, etc.).

La clase AccessSiteMapProvider se deriva de la clase StaticSiteMapProvider y recupera su información de una base de datos de Microsoft Access utilizando las consultas SQL básicas así como los objetos OleDbCommand y OleDbDataReader.

Por último, AccessSiteMapProvider se configura para que sea el proveedor predeterminado en el archivo Web.config, como se muestra en el ejemplo de código siguiente.

<configuration>
  <system.web>
    <siteMap defaultProvider="AccessSiteMapProvider">
      <providers>
        <add 
          name="AccessSiteMapProvider"
          type="<type name>"
          accessSiteMapConnectionString="PROVIDER=MICROSOFT.JET.OLEDB.4.0;DATA SOURCE=<path>\sitemap.mdb "/>
      </providers> 
    </siteMap>
  </system.web>
</configuration>

Para personalizar este ejemplo, reemplace <type name> con el nombre completo de la clase que implementa su proveedor de datos del mapa del sitio. Por ejemplo, en el código de C# anterior, reemplace <type name> con Samples.AspNet.CS.Controls.AccessSiteMapProvider. Si compila el código del proveedor de datos del mapa del sitio y lo coloca en el directorio Bin, la cadena <type name> también debe incluir el nombre del archivo compilado sin la extensión del nombre de archivo. Por ejemplo, si compilara el código C# anterior en un archivo denominado Samples.AspNet.dll, reemplazaría <type name> con Samples.AspNet.CS.Controls.AccessSiteMapProvider.Samples.AspNet. Por último, reemplace <path> con la ruta de acceso física absoluta a su base de datos de mapa del sitio.

Nota:
Cuando se hereda del control StaticSiteMapProvider, deben reemplazarse los miembros siguientes: BuildSiteMap y GetRootNodeCore.

Programación sólida

Si está ampliando la clase StaticSiteMapProvider, los tres métodos más importantes son GetRootNodeCore, Initialize y BuildSiteMap. Los métodos Clear y FindSiteMapNode tienen implementaciones predeterminadas que resultan suficientes para la mayoría de los proveedores personalizados.

Vea también

Conceptos

Información general sobre la exploración del sitio de ASP.NET

Proteger la exploración del sitio de ASP.NET

Proteger el acceso a datos

Referencia

StaticSiteMapProvider

SiteMapProvider

BuildSiteMap

OleDbCommand

OleDbDataReader

SiteMapNode

SiteMap

Otros recursos

Seguridad de aplicaciones ASP.NET en entornos alojados en host