ServiceBehaviorAttribute.TransactionIsolationLevel Propriété

Définition

Spécifie le niveau d’isolation des nouvelles transactions créées à l’intérieur du service et des transactions entrantes transmises à partir d’un client.Specifies the transaction isolation level for new transactions created inside the service, and incoming transactions flowed from a client.

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

Valeur de propriété

Valeur IsolationLevel précisant le niveau d’isolation de la transaction.A IsolationLevel value that specifies the transaction isolation level. La valeur par défaut est Unspecified.The default is Unspecified.

Exceptions

La valeur ne fait pas partie des valeurs IsolationLevel.The value is not one of the IsolationLevel values.

Exemples

L’exemple de code suivant affecte au niveau d’isolation des transactions la valeur ReadCommitted, ne prend pas en charge les transactions concurrentes, exige une transaction passée à partir de l’appel de méthode et valide automatiquement la transaction si aucune exception non gérée ne se produit.The following code example sets the transaction isolation level to ReadCommitted, does not support concurrent transactions, requires a flowed transaction from the method call, and commits the transaction automatically if no unhandled exception occurs.

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

La liaison sous-jacente doit prendre en charge les transactions passées pour l’exemple de code suivant pour s’exécuter correctement.The underlying binding must support flowed transactions for the following code example to execute properly. Pour prendre en charge les transactions passées à l'aide de WSHttpBinding, par exemple, affectez la valeur TransactionFlow à la propriété true dans le code ou dans un fichier de configuration de l'application.To support flowed transactions using the WSHttpBinding, for example, set the TransactionFlow property to true in code or in an application configuration file. L'exemple de code suivant montre un fichier de configuration pour l'exemple précédent.The following code example shows a configuration file for the preceding sample.

<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>

Remarques

Le niveau d’isolation sous lequel votre transaction est exécutée détermine la manière dont les données sont traitées lorsque vous apportez des modifications à d’autres transactions, ainsi que la durée pendant laquelle votre transaction doit conserver des verrous pour se protéger contre ces modifications.The isolation level in which your transaction runs determines how data is treated when changes are made in other transactions and how long your transaction must hold locks to protect against these changes. Par exemple, la valeur par défaut, Unspecified, indique qu'aucune mise à jour ou insertion ne peut intervenir tant que la transaction n'est pas terminée.For example, the default value, Unspecified, specifies that no updating or inserting can occur until the transaction is complete.

Cette propriété peut également être utilisée pour restreindre le niveau d'isolation de transactions entrantes transmises à partir d'un client.This property can also be used to restrict the isolation level of incoming transactions flowed from a client.

S’applique à