ServiceBehaviorAttribute.InstanceContextMode Propriedade

Definição

Obtém ou define o valor que indica quando novos objetos de serviço são criados.Gets or sets the value that indicates when new service objects are created.

public:
 property System::ServiceModel::InstanceContextMode InstanceContextMode { System::ServiceModel::InstanceContextMode get(); void set(System::ServiceModel::InstanceContextMode value); };
public System.ServiceModel.InstanceContextMode InstanceContextMode { get; set; }
member this.InstanceContextMode : System.ServiceModel.InstanceContextMode with get, set
Public Property InstanceContextMode As InstanceContextMode

Valor da propriedade

Um dos valores InstanceContextMode; o valor padrão é PerSession.One of the InstanceContextMode values; the default value is PerSession.

Exceções

O valor não é um dos valores InstanceContextMode.The value is not one of the InstanceContextMode values.

Exemplos

O exemplo de código a seguir ServiceBehaviorAttribute demonstra as propriedades.The following code example demonstrates the ServiceBehaviorAttribute properties. A BehaviorService classe usa o ServiceBehaviorAttribute atributo para indicar que:The BehaviorService class uses the ServiceBehaviorAttribute attribute to indicate that:

  • Os métodos de implementação são invocados no thread da interface do usuário.Implementation methods are invoked on the UI thread.

  • Há um objeto de serviço para cada sessão.There is one service object for each session.

  • O serviço é de thread único e não oferece suporte a chamadas reentrantes.The service is single-threaded and does not support reentrant calls.

Além disso, no nível da operação, OperationBehaviorAttribute os valores indicam que TxWork o método é automaticamente inscrito em transações fluidas ou cria uma nova transação para fazer o trabalho e que a transação é confirmada automaticamente se não for tratada a exceção não ocorre.Furthermore, at the operation level, the OperationBehaviorAttribute values indicate that the TxWork method automatically enlists in flowed transactions or creates a new transaction to do the work, and that the transaction is committed automatically if an unhandled exception does not occur.

using System;
using System.ServiceModel;
using System.Transactions;

namespace Microsoft.WCF.Documentation
{
  [ServiceContract(
    Namespace="http://microsoft.wcf.documentation", 
    SessionMode=SessionMode.Required
  )]
  public interface IBehaviorService
  {
    [OperationContract]
    string TxWork(string message);
  }

  // Note: To use the TransactionIsolationLevel property, you 
  // must add a reference to the System.Transactions.dll assembly.
  /* The following service implementation:
   *   -- Processes messages on one thread at a time
   *   -- Creates one service object per session
   *   -- Releases the service object when the transaction commits
   */
  [ServiceBehavior(
    ConcurrencyMode=ConcurrencyMode.Single,
    InstanceContextMode=InstanceContextMode.PerSession,
    ReleaseServiceInstanceOnTransactionComplete=true
  )]
  public class BehaviorService : IBehaviorService, IDisposable
  {
    Guid myID;

    public BehaviorService()
    {
      myID = Guid.NewGuid();
      Console.WriteLine(
        "Object "
        + myID.ToString()
        + " created.");
    }

    /*
     * The following operation-level behaviors are specified:
     *   -- The executing transaction is committed when
     *        the operation completes without an 
     *        unhandled exception
     *   -- Always executes under a flowed transaction.
     */
    [OperationBehavior(
      TransactionAutoComplete = true,
      TransactionScopeRequired = true
    )]
    [TransactionFlow(TransactionFlowOption.Mandatory)]
    public string TxWork(string message)
    {
      // Do some transactable work.
      Console.WriteLine("TxWork called with: " + message);
      // Display transaction information.

      TransactionInformation info = Transaction.Current.TransactionInformation;
      Console.WriteLine("The distributed tx ID: {0}.", info.DistributedIdentifier);
      Console.WriteLine("The tx status: {0}.", info.Status);
      return String.Format("Hello. This was object {0}.",myID.ToString()) ;
    }

    public void Dispose()
    {
      Console.WriteLine(
        "Service "
        + myID.ToString()
        + " is being recycled."
      );
    }
  }
}
Imports System.ServiceModel
Imports System.Transactions

Namespace Microsoft.WCF.Documentation
  <ServiceContract(Namespace:="http://microsoft.wcf.documentation", SessionMode:=SessionMode.Required)> _
  Public Interface IBehaviorService
    <OperationContract> _
    Function TxWork(ByVal message As String) As String
  End Interface

  ' Note: To use the TransactionIsolationLevel property, you 
  ' must add a reference to the System.Transactions.dll assembly.
'   The following service implementation:
'   *   -- Processes messages on one thread at a time
'   *   -- Creates one service object per session
'   *   -- Releases the service object when the transaction commits
'   
    <ServiceBehavior(ConcurrencyMode:=ConcurrencyMode.Single, InstanceContextMode:=InstanceContextMode.PerSession, _
                     ReleaseServiceInstanceOnTransactionComplete:=True)> _
    Public Class BehaviorService
        Implements IBehaviorService, IDisposable
        Private myID As Guid

        Public Sub New()
            myID = Guid.NewGuid()
            Console.WriteLine("Object " & myID.ToString() & " created.")
        End Sub

        '    
        '     * The following operation-level behaviors are specified:
        '     *   -- The executing transaction is committed when
        '     *        the operation completes without an 
        '     *        unhandled exception
        '     *   -- Always executes under a flowed transaction.
        '     
        <OperationBehavior(TransactionAutoComplete:=True, TransactionScopeRequired:=True), TransactionFlow(TransactionFlowOption.Mandatory)> _
        Public Function TxWork(ByVal message As String) As String Implements IBehaviorService.TxWork
            ' Do some transactable work.
            Console.WriteLine("TxWork called with: " & message)
            ' Display transaction information.

            Dim info As TransactionInformation = Transaction.Current.TransactionInformation
            Console.WriteLine("The distributed tx ID: {0}.", info.DistributedIdentifier)
            Console.WriteLine("The tx status: {0}.", info.Status)
            Return String.Format("Hello. This was object {0}.", myID.ToString())
        End Function

        Public Sub Dispose() Implements IDisposable.Dispose
            Console.WriteLine("Service " & myID.ToString() & " is being recycled.")
        End Sub
    End Class
End Namespace

A associação subjacente deve dar suporte a transações fluidas para que o exemplo de código a seguir seja executado corretamente.The underlying binding must support flowed transactions for the following code example to execute properly. Para dar suporte a transações fluidas WSHttpBindingusando o, por exemplo, TransactionFlow defina a true Propriedade como no código ou em um arquivo de configuração de aplicativo.To support flowed transactions using the WSHttpBinding, for example, set the TransactionFlow property to true in code or in an application configuration file. O exemplo de código a seguir mostra o arquivo de configuração para o exemplo anterior.The following code example shows the configuration file for the preceding sample.

<configuration>
  <system.serviceModel>
    <services>
      <service  
        name="Microsoft.WCF.Documentation.BehaviorService" 
        behaviorConfiguration="metadataAndDebugEnabled"
      >
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8080/SampleService"/>
          </baseAddresses>
        </host>
        <!--
          Note:
            This example code uses the WSHttpBinding to support transactions using the 
            WS-AtomicTransactions (WS-AT) protocol. WSHttpBinding is configured to use the  
            protocol, but the protocol is not enabled on some computers. Use the xws_reg -wsat+ 
            command to enable the WS-AtomicTransactions protocol in the MSDTC service.          
          -->
        <endpoint 
           contract="Microsoft.WCF.Documentation.IBehaviorService"
           binding="wsHttpBinding"
           bindingConfiguration="wsHttpBindingWithTXFlow"
           address="http://localhost:8080/BehaviorService"
          />
        <endpoint 
           contract="Microsoft.WCF.Documentation.IBehaviorService"
           binding="netTcpBinding"
           bindingConfiguration="netTcpBindingWithTXFlow"
           address="net.tcp://localhost:8081/BehaviorService"
          />
        <endpoint
          address="mex"
          binding="mexHttpBinding"
          contract="IMetadataExchange"
        />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="metadataAndDebugEnabled">
          <serviceDebug
            includeExceptionDetailInFaults="true"
          />
          <serviceMetadata
            httpGetEnabled="true"
            httpGetUrl=""
          />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <!-- binding configuration - configures a WSHttpBinding to require transaction flow -->
    <bindings>
      <wsHttpBinding>
        <binding name="wsHttpBindingWithTXFlow" transactionFlow="true" />
      </wsHttpBinding>
      <netTcpBinding>
        <binding name="netTcpBindingWithTXFlow" transactionFlow="true" />
      </netTcpBinding>
    </bindings>
  </system.serviceModel>
</configuration>

Comentários

Use a InstanceContextMode propriedade para especificar quando novos objetos de serviço são criados.Use the InstanceContextMode property to specify when new service objects are created. Como o objeto de serviço não está conectado diretamente ao canal de comunicação, o tempo de vida dos objetos de serviço é independente do tempo de vida do canal entre um cliente e o aplicativo de serviço.Because the service object is not directly connected to the communicating channel, the lifetime of the service objects is independent of the lifetime of the channel between a client and the service application. O valor padrão, PerSession, instrui o aplicativo de serviço a criar um novo objeto de serviço quando uma nova sessão de comunicação é estabelecida entre um cliente e o aplicativo de serviço.The default value, PerSession, instructs the service application to create a new service object when a new communication session is established between a client and the service application. As chamadas subsequentes na mesma sessão são manipuladas pelo mesmo objeto.Subsequent calls in the same session are handled by the same object.

PerSessionindica que cada objeto de serviço manipula solicitações de um canal de cliente.PerSession indicates that each service object handles requests from one client channel.

Observação

A InstanceContextMode Propriedade interage com algumas outras configurações.The InstanceContextMode property interacts with some other settings. Por exemplo, se o InstanceContextMode valor for definido como Single o resultado, o serviço só poderá processar uma mensagem por vez, a menos que você também defina ConcurrencyMode o valor Multiplecomo.For example, if the InstanceContextMode value is set to Single the result is that your service can only process one message at a time unless you also set the ConcurrencyMode value to Multiple. Essa propriedade também produz o comportamento em combinação com ServiceContractAttribute.SessionMode a propriedade.This property also produces behavior in combination with the ServiceContractAttribute.SessionMode property. Para obter detalhes, consulte sessões, instanciação e simultaneidade.For details, see Sessions, Instancing, and Concurrency.

Para o comportamento de tempo de vida singleton (por exemplo, se o ServiceHost aplicativo host chama o construtor e passa um objeto para usar como o serviço), a InstanceContextMode classe Singlede serviço deve ser definida como, ou uma exceção é lançada em tempo de execução.For singleton lifetime behavior (for example, if the host application calls the ServiceHost constructor and passes an object to use as the service), the service class must set InstanceContextMode to Single, or an exception is thrown at run time.

Aplica-se a