ServiceBehaviorAttribute.TransactionIsolationLevel Propiedad

Definición

Espacio de nombres:

System.ServiceModel

Ensamblado:

System.ServiceModel.dll

Especifica el nivel de aislamiento de transacción para las nuevas transacciones creadas dentro del servicio y las transacciones entrantes que han fluido desde un cliente.

public:
 property System::Transactions::IsolationLevel TransactionIsolationLevel { System::Transactions::IsolationLevel get(); void set(System::Transactions::IsolationLevel value); };

public System.Transactions.IsolationLevel TransactionIsolationLevel { get; set; }

member this.TransactionIsolationLevel : System.Transactions.IsolationLevel with get, set

Public Property TransactionIsolationLevel As IsolationLevel

Valor de propiedad

IsolationLevel

Valor IsolationLevel que especifica el nivel de aislamiento de la transacción. De manera predeterminada, es Unspecified.

Excepciones

ArgumentOutOfRangeException

El valor no es uno de los valores de IsolationLevel.

Ejemplos

El ejemplo de código siguiente establece el nivel de aislamiento de transacción como ReadCommitted, no admite transacciones simultáneas, requiere una transacción de flujo de la llamada al método y confirma automáticamente la transacción si no se produce ninguna excepción no controlada.

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
   *   -- Does not release the service object when the transaction commits
   *   -- The isolation level is read committed.
   */
  [ServiceBehavior(
    ConcurrencyMode=ConcurrencyMode.Single,
    InstanceContextMode=InstanceContextMode.PerSession,
    ReleaseServiceInstanceOnTransactionComplete=false,
    TransactionIsolationLevel=System.Transactions.IsolationLevel.ReadCommitted
  )]
  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:
     *   -- Always executes under a transaction scope.
     *   -- The transaction scope is completed when the operation terminates
     *       without an unhandled exception.
     */
    [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
'   *   -- Does not release the service object when the transaction commits
'   *   -- The isolation level is read committed.
'   
    <ServiceBehavior(ConcurrencyMode:=ConcurrencyMode.Single, InstanceContextMode:=InstanceContextMode.PerSession, _
      ReleaseServiceInstanceOnTransactionComplete:=False, TransactionIsolationLevel:=System.Transactions.IsolationLevel.ReadCommitted)> _
    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:
        '     *   -- Always executes under a transaction scope.
        '     *   -- The transaction scope is completed when the operation terminates
        '     *       without an unhandled exception.
        '     
        <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

El enlace subyacente debe admitir transacciones de flujo para que el ejemplo de código siguiente se ejecute correctamente. Para admitir transacciones de flujo con WSHttpBinding, por ejemplo, establezca la propiedad TransactionFlow como true en el código o en un archivo de configuración de la aplicación. El ejemplo de código siguiente muestra un archivo de configuración para el ejemplo anterior:

<configuration>
  <system.serviceModel>
    <services>
      <service  
        name="Microsoft.WCF.Documentation.BehaviorService" 
        behaviorConfiguration="mex"
        >
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8080/BehaviorService"/>
            <add baseAddress="net.tcp://localhost:8081/BehaviorService"/>
          </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"
          />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="mex">
          <serviceMetadata httpGetEnabled="true"/>
        </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>

Comentarios

El nivel de aislamiento en el que su transacción se ejecuta determina cómo se tratan los datos cuando se realizan modificaciones en otras transacciones y cuánto tiempo debe contener los bloqueos su transacción para protegerse contra estos cambios. Por ejemplo, el valor predeterminado, Unspecified, especifica que no se puede actualizar ni insertar hasta que la transacción haya finalizado.

Esta propiedad también se puede utilizar para restringir el nivel de aislamiento de transacciones entrantes que han fluido de un cliente.