如何：检查和修改服务上的消息

通过实现 System.ServiceModel.Dispatcher.IDispatchMessageInspector 并将它插入服务运行时，可以检查或修改通过 Windows Communication Foundation (WCF) 客户端的传入或传出消息。 有关详细信息，请参阅扩展 Dispatcher。 服务上的等效功能为 System.ServiceModel.Dispatcher.IClientMessageInspector。

检查或修改消息

1. 实现 System.ServiceModel.Dispatcher.IDispatchMessageInspector 接口。

2. 根据您希望轻松插入服务消息检查器的范围，实现 System.ServiceModel.Description.IServiceBehavior、System.ServiceModel.Description.IEndpointBehavior 或 System.ServiceModel.Description.IContractBehavior 接口。

3. 在 ICommunicationObject.Open 上调用 System.ServiceModel.ServiceHost 方法之前，先插入行为。 有关详细信息，请参阅使用行为配置和扩展运行时。

示例

下面的代码示例按顺序演示以下各项：

• 服务检查器实现。

• 插入检查器的服务行为。

• 在服务应用程序中加载和运行该行为的配置文件。

#region IDispatchMessageInspector Members
public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, IClientChannel channel, InstanceContext instanceContext)
{
  Console.WriteLine("IDispatchMessageInspector.AfterReceiveRequest called.");
  return null;
}

public void BeforeSendReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
{
  Console.WriteLine("IDispatchMessageInspector.BeforeSendReply called.");
}
#endregion

#Region "IDispatchMessageInspector Members"
        Public Function AfterReceiveRequest(ByRef request As System.ServiceModel.Channels.Message, _
                           ByVal channel As IClientChannel, ByVal instanceContext As InstanceContext) _
                           As Object Implements IDispatchMessageInspector.AfterReceiveRequest
            Console.WriteLine("IDispatchMessageInspector.AfterReceiveRequest called.")
            Return Nothing
        End Function

        Public Sub BeforeSendReply(ByRef reply As System.ServiceModel.Channels.Message, ByVal correlationState As Object) _
        Implements IDispatchMessageInspector.BeforeSendReply
            Console.WriteLine("IDispatchMessageInspector.BeforeSendReply called.")
        End Sub
#End Region

#region IServiceBehavior Members
public void AddBindingParameters(
  ServiceDescription serviceDescription,
  ServiceHostBase serviceHostBase,
  System.Collections.ObjectModel.Collection<ServiceEndpoint> endpoints,
  BindingParameterCollection bindingParameters
)
{ return; }

public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
{
  foreach (ChannelDispatcher chDisp in serviceHostBase.ChannelDispatchers)
  {
    foreach (EndpointDispatcher epDisp in chDisp.Endpoints)
    {
      epDisp.DispatchRuntime.MessageInspectors.Add(new Inspector());
      foreach (DispatchOperation op in epDisp.DispatchRuntime.Operations)
        op.ParameterInspectors.Add(new Inspector());
    }
  }
}

#Region "IServiceBehavior Members"
        Public Sub AddBindingParameters(ByVal serviceDescription As ServiceDescription, _
                       ByVal serviceHostBase As ServiceHostBase, ByVal endpoints As _
                       System.Collections.ObjectModel.Collection(Of ServiceEndpoint), _
                       ByVal bindingParameters As BindingParameterCollection) Implements IServiceBehavior.AddBindingParameters
            Return
        End Sub

        Public Sub ApplyDispatchBehavior(ByVal serviceDescription As ServiceDescription, _
                                         ByVal serviceHostBase As ServiceHostBase) Implements _
                                         IServiceBehavior.ApplyDispatchBehavior
            For Each chDisp As ChannelDispatcher In serviceHostBase.ChannelDispatchers
                For Each epDisp As EndpointDispatcher In chDisp.Endpoints
                    epDisp.DispatchRuntime.MessageInspectors.Add(New Inspector())
                    For Each op As DispatchOperation In epDisp.DispatchRuntime.Operations
                        op.ParameterInspectors.Add(New Inspector())
                    Next op
                Next epDisp
            Next chDisp
        End Sub

<configuration>
  <system.serviceModel>
    <services>
      <service 
        name="Microsoft.WCF.Documentation.SampleService"
        behaviorConfiguration="metadataSupport">
        <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="metadataSupport">
          <serviceMetadata httpGetEnabled="true" httpGetUrl=""/>
          <serviceInterceptors />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <extensions>
      <behaviorExtensions>
        <add 
          name="serviceInterceptors" 
          type="Microsoft.WCF.Documentation.InspectorInserter, HostApplication, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null"
        />
      </behaviorExtensions>
    </extensions>
  </system.serviceModel>
</configuration>

另请参阅

• System.ServiceModel.Dispatcher.IClientMessageInspector
• System.ServiceModel.Dispatcher.IDispatchMessageInspector
• 使用行为配置和扩展运行时