Exemplo de Provedor de Mapa do Site do Access
Ilustra um provedor completo de mapa de site baseado em Access.
Exemplo
Descrição
O exemplo de código a seguir demonstra como você pode estender a classe StaticSiteMapProvider para usar o Microsoft Access como um provedor de mapa de sites.O provedor de mapa do site usa o provedor de dados do .NET Framework para OLE DB para conectar-se para o banco de dados 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
Comentários
Para criar a tabela do Access que é usada pelo código de exemplo anterior como armazenamento de dados do mapa do site, emita a consulta de definição de dados a seguir em um banco de dados Access novo ou existente, e então salve o banco de dados Access com o nome de arquivo Sitemap.mdb.
CREATE TABLE SiteMap
(
URL Text (255) UNIQUE,
NAME Text (255) NOT NULL,
PARENTNODEID Int32,
CONSTRAINT NODEID PRIMARY KEY (URL, NAME)
)
Preencha a tabela com os seguintes tipos de dados, listando arquivos que você tem no seu site da Web ou arquivos que você pode criar.A tabela a seguir mostra um exemplo listagem de arquivos.
IdentificaçãoDoNó |
URL |
Nome |
IdentificaçãoDoNóPai |
|---|---|---|---|
1 |
Padrão.aspx |
Padrão |
null (célula vazia) |
2 |
Catálogo.aspx |
Catálogo |
1 |
3 |
Sobrenós.aspx |
Contate-nos |
1 |
.gif "Observação") Observação: |
|---|
Como as fontes de dados contêm diferentes sintaxes SQL, alguns comandos irão funcionar com uma fonte de dados e não com outra.Por esse motivo, é recomendável que você crie um provedor mapa do site que seja específico para sua fonte de dados, mesmo se você estiver usando o provedor de dados do .NET Framework para ODBC ou o provedor de dados do .NET Framework para OLE DB para acessar sua fonte de dados (por exemplo, SybaseSiteMapProvider, OracleSiteMapProvider, e assim por diante). |
A classe AccessSiteMapProvider deriva da classe StaticSiteMapProvider e recupera suas informações de banco de dados Access usando consultas SQL básicas, bem como objetos OleDbCommand e OleDbDataReader.
Finalmente, o AccessSiteMapProvider é configurado para ser o provedor padrão no arquivo Web.config, como mostrado no exemplo de código a seguir.
<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 neste exemplo, substitua o <type name> por um nome totalmente qualificado da classe que implementa o provedor de dados do mapa do site.Por exemplo, no código C# acima, você poderia substituir <type name> com Samples.AspNet.CS.Controls.AccessSiteMapProvider.Se você compilar o código do provedor de dados do mapa do site e colocá-lo no diretório Bin, a sequência <type name> também deve incluir o nome do seu arquivo compilado sem a extensão de nome de arquivo.Por exemplo, se você compilou o código em C# acima em um arquivo chamado Samples.AspNet.dll, você poderia substituir <type name> com Samples.AspNet.CS.Controls.AccessSiteMapProvider.Samples.AspNet.Finalmente, substitua <path> pelo caminho físico absoluto para o banco de dados de mapa de sites.
| Observação: |
|---|
Quando você herdar de StaticSiteMapProvider, você deve substituir os seguintes membros: BuildSiteMap e GetRootNodeCore. |
Programação robusta
Se você estiver estendendo a classe StaticSiteMapProvider, os três métodos mais importantes são GetRootNodeCore, Initialize e BuildSiteMap.Os métodos ClearFindSiteMapNode tem implementações padrão que são suficientes para a maioria das implementações do provedor personalizado.
Consulte também
Conceitos
Visão geral sobre navegação em sites do ASP.NET
Tornando navegação em sites do ASP.NET seguro