ServiceBehaviorAttribute.TransactionIsolationLevel Propriété

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 qui spécifie le niveau d’isolation des transactions. La valeur par défaut est Unspecified.

Exceptions

Exemples

L’exemple de code suivant définit le niveau ReadCommittedd’isolation de transaction sur , ne prend pas en charge les transactions simultanées, nécessite une transaction transmise à partir de l’appel de méthode et valide automatiquement la transaction si aucune exception non gérée ne se produit.

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 transmises pour que l’exemple de code suivant s’exécute correctement. Pour prendre en charge les transactions transmises à l’aide de la WSHttpBindingpropriété, par exemple, définissez la propriété true dans le TransactionFlow code ou dans un fichier de configuration d’application. L’exemple de code suivant montre un fichier de configuration pour l’exemple précédent.

<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 dans lequel votre transaction s’exécute détermine la façon dont les données sont traitées lorsque des modifications sont apportées dans d’autres transactions et combien de temps votre transaction doit contenir des verrous pour se protéger contre ces modifications. Par exemple, la valeur par défaut, Unspecifiedspécifie qu’aucune mise à jour ou insertion ne peut se produire tant que la transaction n’est pas terminée.

Cette propriété peut également être utilisée pour limiter le niveau d’isolation des transactions entrantes transmises à partir d’un client.