IServiceBehavior.ApplyDispatchBehavior Method (ServiceDescription, ServiceHostBase)

 
System_CAPS_noteNote

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Provides the ability to change run-time property values or insert custom extension objects such as error handlers, message or parameter interceptors, security extensions, and other custom extension objects.

Namespace:   System.ServiceModel.Description
Assembly:  System.ServiceModel (in System.ServiceModel.dll)

void ApplyDispatchBehavior(
	ServiceDescription serviceDescription,
	ServiceHostBase serviceHostBase
)

Parameters

serviceDescription
Type: System.ServiceModel.Description.ServiceDescription

The service description.

serviceHostBase
Type: System.ServiceModel.ServiceHostBase

The host that is currently being built.

Implement the ApplyDispatchBehavior method to inspect or modify the ServiceHostBase object that is being constructed in order to support some custom execution scenario.

System_CAPS_noteNote

All of the IServiceBehavior methods pass System.ServiceModel.Description.ServiceDescription and System.ServiceModel.ServiceHostBase objects as a parameters. The ServiceDescription parameter is for examination and insertion of customizations only; if you otherwise modify these objects the execution behavior is undefined.

The following code example shows the use of a service behavior specified in a configuration file to insert a custom error handler in a service application. In this example, the error handler catches all exceptions and converts them into a custom GreetingFault SOAP fault that is then returned to the client.

The following IServiceBehavior implementation adds no binding parameter objects, adds the custom System.ServiceModel.Dispatcher.IErrorHandler object to each ChannelDispatcher.ErrorHandlers property, and validates that each operation of the service to which the service behavior is applied and has a System.ServiceModel.FaultContractAttribute of type GreetingFault.

// 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

In this example, the behavior class also implements System.ServiceModel.Configuration.BehaviorExtensionElement, which enables the service behavior to be inserted by using it in an application configuration file, as the following code example demonstrates.

.NET Framework
Available since 3.0
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