IErrorHandler.HandleError(Exception) Método

Definição

Habilita o processamento de erro e retorna um valor que indica se o dispatcher anula a sessão e o contexto da instância em determinados casos.Enables error-related processing and returns a value that indicates whether the dispatcher aborts the session and the instance context in certain cases.

public:
 bool HandleError(Exception ^ error);
public:
 bool HandleError(Exception ^ exception);
public bool HandleError (Exception error);
public bool HandleError (Exception exception);
abstract member HandleError : Exception -> bool
abstract member HandleError : Exception -> bool
Public Function HandleError (error As Exception) As Boolean
Public Function HandleError (exception As Exception) As Boolean

Parâmetros

errorexception
Exception

A exceção lançada durante o processamento.The exception thrown during processing.

Retornos

Boolean

true se o WCF (Windows Communication Foundation) não deve anular a sessão (se houver) e o contexto de instância se o contexto de instância não é Single; caso contrário, false.true if Windows Communication Foundation (WCF) should not abort the session (if there is one) and instance context if the instance context is not Single; otherwise, false. O padrão é false.The default is false.

Exemplos

O exemplo de código a seguir demonstra um serviço que implementa IErrorHandler que retorna apenas FaultException<TDetail> do tipo GreetingFault quando um método de serviço gera uma exceção gerenciada.The following code example demonstrates a service that implements IErrorHandler that returns only FaultException<TDetail> of type GreetingFault when a service method throws a managed exception.

#region IErrorHandler Members
public bool HandleError(Exception error)
{
  Console.WriteLine("HandleError called.");
  // Returning true indicates you performed your behavior.
  return true;
}

// This is a trivial implementation that converts Exception to FaultException<GreetingFault>.
public void ProvideFault(
  Exception error,
  MessageVersion ver,
  ref Message msg
)
{
  Console.WriteLine("ProvideFault called. Converting Exception to GreetingFault....");
  FaultException<GreetingFault> fe
    = new FaultException<GreetingFault>(new GreetingFault(error.Message));
  MessageFault fault = fe.CreateMessageFault();
  msg = Message.CreateMessage(
    ver,
    fault,
    "http://microsoft.wcf.documentation/ISampleService/SampleMethodGreetingFaultFault"
  );
}
#endregion
#Region "IErrorHandler Members"
Public Function HandleError(ByVal [error] As Exception) As Boolean Implements IErrorHandler.HandleError
  Console.WriteLine("HandleError called.")
  ' Returning true indicates you performed your behavior.
  Return True
End Function

' This is a trivial implementation that converts Exception to FaultException<GreetingFault>.
Public Sub ProvideFault(ByVal [error] As Exception, ByVal ver As MessageVersion, ByRef msg As Message) Implements IErrorHandler.ProvideFault
  Console.WriteLine("ProvideFault called. Converting Exception to GreetingFault....")
  Dim fe As New FaultException(Of GreetingFault)(New GreetingFault([error].Message))
  Dim fault As MessageFault = fe.CreateMessageFault()
  msg = Message.CreateMessage(ver, fault, "http://microsoft.wcf.documentation/ISampleService/SampleMethodGreetingFaultFault")
End Sub
#End Region

O exemplo de código a seguir mostra como usar um comportamento de serviço para adicionar a IErrorHandler implementação à ErrorHandlers propriedade.The following code example shows how to use a service behavior to add the IErrorHandler implementation to the ErrorHandlers property.

// This behavior modifies no binding parameters.
#region IServiceBehavior Members
public void AddBindingParameters(
  ServiceDescription description,
  ServiceHostBase serviceHostBase,
  System.Collections.ObjectModel.Collection<ServiceEndpoint> endpoints,
  System.ServiceModel.Channels.BindingParameterCollection parameters
)
{
  return;
}

// This behavior is an IErrorHandler implementation and
// must be applied to each ChannelDispatcher.
public void ApplyDispatchBehavior(ServiceDescription description, ServiceHostBase serviceHostBase)
{
  Console.WriteLine("The EnforceGreetingFaultBehavior has been applied.");
  foreach(ChannelDispatcher chanDisp in serviceHostBase.ChannelDispatchers)
  {
    chanDisp.ErrorHandlers.Add(this);
  }
}

// This behavior requires that the contract have a SOAP fault with a detail type of GreetingFault.
public void Validate(ServiceDescription description, ServiceHostBase serviceHostBase)
{
  Console.WriteLine("Validate is called.");
  foreach (ServiceEndpoint se in description.Endpoints)
  {
    // Must not examine any metadata endpoint.
    if (se.Contract.Name.Equals("IMetadataExchange")
      && se.Contract.Namespace.Equals("http://schemas.microsoft.com/2006/04/mex"))
      continue;
    foreach (OperationDescription opDesc in se.Contract.Operations)
    {
      if (opDesc.Faults.Count == 0)
        throw new InvalidOperationException(String.Format(
          "EnforceGreetingFaultBehavior requires a "
          + "FaultContractAttribute(typeof(GreetingFault)) in each operation contract.  "
          + "The \"{0}\" operation contains no FaultContractAttribute.",
          opDesc.Name)
        );
      bool gfExists = false;
      foreach (FaultDescription fault in opDesc.Faults)
      {
        if (fault.DetailType.Equals(typeof(GreetingFault)))
        {
          gfExists = true;
          continue;
        }
      }
      if (gfExists == false)
      {
        throw new InvalidOperationException(
"EnforceGreetingFaultBehavior requires a FaultContractAttribute(typeof(GreetingFault)) in an operation contract."
        );
      }
    }
  }
}
#endregion
' This behavior modifies no binding parameters.
#Region "IServiceBehavior Members"
Public Sub AddBindingParameters(ByVal description As ServiceDescription, ByVal serviceHostBase As ServiceHostBase, ByVal endpoints As System.Collections.ObjectModel.Collection(Of ServiceEndpoint), ByVal parameters As System.ServiceModel.Channels.BindingParameterCollection) Implements IServiceBehavior.AddBindingParameters
  Return
End Sub

' This behavior is an IErrorHandler implementation and 
' must be applied to each ChannelDispatcher.
Public Sub ApplyDispatchBehavior(ByVal description As ServiceDescription, ByVal serviceHostBase As ServiceHostBase) Implements IServiceBehavior.ApplyDispatchBehavior
  Console.WriteLine("The EnforceGreetingFaultBehavior has been applied.")
  For Each chanDisp As ChannelDispatcher In serviceHostBase.ChannelDispatchers
    chanDisp.ErrorHandlers.Add(Me)
  Next chanDisp
End Sub

' This behavior requires that the contract have a SOAP fault with a detail type of GreetingFault.
Public Sub Validate(ByVal description As ServiceDescription, ByVal serviceHostBase As ServiceHostBase) Implements IServiceBehavior.Validate
  Console.WriteLine("Validate is called.")
  For Each se As ServiceEndpoint In description.Endpoints
    ' Must not examine any metadata endpoint.
    If se.Contract.Name.Equals("IMetadataExchange") AndAlso se.Contract.Namespace.Equals("http://schemas.microsoft.com/2006/04/mex") Then
      Continue For
    End If
    For Each opDesc As OperationDescription In se.Contract.Operations
      If opDesc.Faults.Count = 0 Then
        Throw New InvalidOperationException(String.Format("EnforceGreetingFaultBehavior requires a " & "FaultContractAttribute(typeof(GreetingFault)) in each operation contract.  " & "The ""{0}"" operation contains no FaultContractAttribute.", opDesc.Name))
      End If
      Dim gfExists As Boolean = False
      For Each fault As FaultDescription In opDesc.Faults
        If fault.DetailType.Equals(GetType(GreetingFault)) Then
          gfExists = True
          Continue For
        End If
      Next fault
      If gfExists = False Then
        Throw New InvalidOperationException("EnforceGreetingFaultBehavior requires a FaultContractAttribute(typeof(GreetingFault)) in an operation contract.")
      End If
    Next opDesc
  Next se
End Sub
#End Region

O exemplo de código a seguir mostra como configurar o serviço para carregar o comportamento do serviço usando um arquivo de configuração de aplicativo.The following code example shows how to configure the service to load the service behavior using an application configuration file. Para obter mais detalhes sobre como expor um comportamento de serviço em um arquivo de configuração, consulte IServiceBehavior .For more details about how to expose a service behavior in a configuration file, see IServiceBehavior.

<configuration>
  <system.serviceModel>
    <services>
      <service 
        name="Microsoft.WCF.Documentation.SampleService"
        behaviorConfiguration="metaAndErrors">
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8080/SampleService"/>
          </baseAddresses>
        </host>
        <endpoint
          address=""
          binding="wsHttpBinding"
          contract="Microsoft.WCF.Documentation.ISampleService"
         />
        <endpoint
          address="mex"
          binding="mexHttpBinding"
          contract="IMetadataExchange"
         />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="metaAndErrors">
          <serviceDebug includeExceptionDetailInFaults="true"/>
          <serviceMetadata httpGetEnabled="true"/>
          <enforceGreetingFaults />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <extensions>
      <behaviorExtensions>
        <add 
          name="enforceGreetingFaults" 
          type="Microsoft.WCF.Documentation.EnforceGreetingFaultBehavior, HostApplication, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null"
        />
      </behaviorExtensions>
    </extensions>
  </system.serviceModel>
</configuration>

Comentários

Use o HandleError método para implementar comportamentos relacionados a erros, como log de erros, notificações do sistema, desligamento do aplicativo e assim por diante, e retornar um valor que especifique se a exceção foi tratada adequadamente.Use the HandleError method to implement error-related behaviors such as error logging, system notifications, shutting down the application, and so on, and return a value that specifies whether the exception has been handled appropriately.

Observação

Como o HandleError método pode ser chamado a partir de vários locais diferentes, não há garantias sobre qual thread o método é chamado.Because the HandleError method can be called from many different places there are no guarantees made about which thread the method is called on. Não dependem do HandleError método que está sendo chamado no thread de operação.Do not depend on HandleError method being called on the operation thread.

Todas as IErrorHandler implementações são chamadas.All IErrorHandler implementations are called. Por padrão (quando o valor de retorno é false ), se houver uma exceção, o Dispatcher anulará qualquer sessão e anulará InstanceContext se o InstanceContextMode for algo diferente de Single .By default (when the return value is false), if there is an exception, the dispatcher aborts any session and aborts the InstanceContext if the InstanceContextMode is anything other than Single. A exceção é considerada sem tratamento e qualquer estado é considerado corrompido.The exception is then considered unhandled and any state is considered corrupt.

Retornar true de HandleError para evitar esse comportamento padrão.Return true from HandleError to prevent this default behavior. Se qualquer manipulador de erro retornar true , ele instruirá o WCF de que é seguro continuar usando o estado associado à solicitação com falha.If any error handler returns true it instructs WCF that it is safe to continue using state associated with the failed request.

Se nenhum manipulador de erro retornar true do HandleError método, a exceção será considerada sem tratamento e a resposta padrão será aplicada, potencialmente resultando em uma anulada System.ServiceModel.InstanceContext e um canal ao se comunicar em um canal de sessão ou a ServiceBehaviorAttribute.InstanceContextMode propriedade não está definida como InstanceContextMode.Single .If no error handler returns true from the HandleError method the exception is considered unhandled and the default response applies, potentially resulting in an aborted System.ServiceModel.InstanceContext and channel when communicating on a session channel or the ServiceBehaviorAttribute.InstanceContextMode property is not set to InstanceContextMode.Single.

O error parâmetro nunca é null e contém o objeto de exceção que foi lançado.The error parameter is never null and contains the exception object that was thrown.

Aplica-se a