Zugreifen auf OperationContext aus einem Workflowdienst

Für den Zugriff auf den OperationContext in einem Workflowdienst müssen Sie die IReceiveMessageCallback-Schnittstelle in einer benutzerdefinierten Ausführungseigenschaft implementieren.Überschreiben Sie die OnReceiveMessage System.Activities.ExecutionProperties)?qualifyHint=False&autoUpgrade=True-Methode, die als Verweis an den OperationContext übergeben wird.In diesem Thema erhalten Sie schrittweise Anweisungen zum Implementieren dieser Ausführungseigenschaft, um einen benutzerdefinierten Header sowie eine benutzerdefinierte Aktivität abzurufen, die diese Eigenschaft zur Laufzeit für Receive sichtbar macht.Die benutzerdefinierte Aktivität implementiert dasselbe Verhalten wie eine <xref:System.ServiceModel.Activities.Sequence>-Aktivität, wenn jedoch Receive darin platziert wird, wird IReceiveMessageCallback aufgerufen, und die OperationContext-Informationen werden abgerufen.In diesem Thema wird zudem veranschaulicht, wie auf den clientseitigen OperationContext zugegriffen wird, um über die ISendMessageCallback-Schnittstelle ausgehende Header hinzuzufügen.

Implementieren des dienstseitigen IReceiveMessageCallback

  1. Erstellen Sie eine leere Visual Studio 2012-Projektmappe.

  2. Fügen Sie der Projektmappe eine neue Konsolenanwendung mit dem Namen Service hinzu.

  3. Fügen Sie Verweise auf die folgenden Assemblys hinzu:

    1. System.Runtime.Serialization

    2. System.ServiceModel

    3. System.ServiceModel.Activities

  4. Fügen Sie eine neue Klasse mit dem Namen ReceiveInstanceIdCallback hinzu, und implementieren Sie IReceiveMessageCallback, wie im folgenden Beispiel veranschaulicht.

    class ReceiveInstanceIdCallback : IReceiveMessageCallback  
    {  
          public const string HeaderName = "InstanceIdHeader";  
          public const string HeaderNS = "http://Microsoft.Samples.AccessingOperationContext";  
    
         public void OnReceiveMessage(System.ServiceModel.OperationContext operationContext, System.Activities.ExecutionProperties activityExecutionProperties)  
          {              
                try  
                {  
                    Guid instanceId = operationContext.IncomingMessageHeaders.GetHeader<Guid>(HeaderName, HeaderNS);  
                    Console.WriteLine("Received a message from a workflow with instanceId = {0}", instanceId);  
                }  
                catch (MessageHeaderException)  
                {  
                    Console.WriteLine("This message must not be from a workflow.");  
                }  
            }  
    }  
    

    In diesem Code wird mit dem an die Methode übergebenen OperationContext auf die Header der eingehenden Nachricht zugegriffen.

Implementieren einer dienstseitigen systemeigenen Aktivität, um dem NativeActivityContext die IReceiveMessageCallback-Implementierung hinzuzufügen

  1. Fügen Sie eine neue, von NativeActivity abgeleitete Klasse mit dem Namen ReceiveInstanceIdScope hinzu.

  2. Fügen Sie lokale Variablen hinzu, um untergeordnete Aktivitäten, Variablen, den aktuellen Aktivitätsindex und einen CompletionCallback-Rückruf zu verfolgen.

    public sealed class ReceiveInstanceIdScope : NativeActivity  
        {  
            Collection<Activity> children;  
            Collection<Variable> variables;  
            Variable<int> currentIndex;  
            CompletionCallback onChildComplete;  
    }  
    
  3. Implementieren des Konstruktors

    public ReceiveInstanceIdScope()  
                : base()  
            {  
                this.children = new Collection<Activity>();  
                this.variables = new Collection<Variable>();  
                this.currentIndex = new Variable<int>();  
            }  
    }  
    
  4. Implementieren Sie die Activities-Eigenschaft und die Variables-Eigenschaft.

    public Collection<Activity> Activities  
    {  
         get { return this.children; }  
    }  
    
    public Collection<Variable> Variables  
    {  
        get { return this.variables; }  
    }  
    
  5. Überschreiben Sie CacheMetadata.

    protected override void CacheMetadata(NativeActivityMetadata metadata)  
    {  
        //call base.CacheMetadata to add the Activities and Variables to this activity's metadata  
        base.CacheMetadata(metadata);  
        //add the private implementation variable: currentIndex   
        metadata.AddImplementationVariable(this.currentIndex);  
    }  
    
  6. Überschreiben Sie Execute.

    protected override void Execute(  
                NativeActivityContext context)  
            {  
                context.Properties.Add("ReceiveInstanceIdCallback", new ReceiveInstanceIdCallback());  
                InternalExecute(context, null);  
            }  
    
            void InternalExecute(NativeActivityContext context, ActivityInstance instance)  
            {  
                //grab the index of the current Activity  
                int currentActivityIndex = this.currentIndex.Get(context);  
                if (currentActivityIndex == Activities.Count)  
                {  
                    //if the currentActivityIndex is equal to the count of MySequence's Activities  
                    //MySequence is complete  
                    return;  
                }  
    
                if (this.onChildComplete == null)  
                {  
                    //on completion of the current child, have the runtime call back on this method  
                    this.onChildComplete = new CompletionCallback(InternalExecute);  
                }  
    
                //grab the next Activity in MySequence.Activities and schedule it  
                Activity nextChild = Activities[currentActivityIndex];  
                context.ScheduleActivity(nextChild, this.onChildComplete);  
    
                //increment the currentIndex  
                this.currentIndex.Set(context, ++currentActivityIndex);  
            }  
    

Implementieren des Workflowdiensts

  1. Öffnen Sie die vorhandene Program-Klasse.

  2. Definieren Sie die folgenden Konstanten:

    class Program  
    {  
       const string addr = "http://localhost:8080/Service";  
       static XName contract = XName.Get("IService", "http://tempuri.org");  
    }  
    
  3. Fügen Sie eine statische Methode mit dem Namen GetWorkflowService hinzu, die den Workflowdienst erstellt.

    static Activity GetServiceWorkflow()  
            {  
                Variable<string> echoString = new Variable<string>();  
    
                Receive echoRequest = new Receive  
                {  
                    CanCreateInstance = true,  
                    ServiceContractName = contract,  
                    OperationName = "Echo",  
                    Content = new ReceiveParametersContent()  
                    {  
                        Parameters = { { "echoString", new OutArgument<string>(echoString) } }  
                    }  
                };  
    
                return new ReceiveInstanceIdScope  
                {  
                    Variables = { echoString },  
                    Activities =  
                    {  
                        echoRequest,  
                        new WriteLine { Text = new InArgument<string>( (e) => "Received: " + echoString.Get(e) ) },  
                        new SendReply  
                        {  
                            Request = echoRequest,  
                            Content = new SendParametersContent()  
                            {  
                                Parameters = { { "result", new InArgument<string>(echoString) } }   
                            }  
                        }  
                    }  
                };  
            }  
    
  4. Hosten Sie den Workflowdienst in der vorhandenen Main-Methode.

    static void Main(string[] args)  
            {  
                string addr = "http://localhost:8080/Service";  
    
                using (WorkflowServiceHost host = new WorkflowServiceHost(GetServiceWorkflow()))  
                {  
                    host.AddServiceEndpoint(contract, new BasicHttpBinding(), addr);  
    
                    host.Open();  
                    Console.WriteLine("Service waiting at: " + addr);  
                    Console.WriteLine("Press [ENTER] to exit");  
                    Console.ReadLine();  
                    host.Close();  
                }  
            }  
    

Implementieren des clientseitigen ISendMessageCallback

  1. Fügen Sie der Projektmappe eine neue Konsolenanwendung mit dem Namen Service hinzu.

  2. Fügen Sie Verweise auf die folgenden Assemblys hinzu:

    1. System.Runtime.Serialization

    2. System.ServiceModel

    3. System.ServiceModel.Activities

  3. Fügen Sie eine neue Klasse mit dem Namen SendInstanceIdCallback hinzu, und implementieren Sie ISendMessageCallback, wie im folgenden Beispiel veranschaulicht.

    class SendInstanceIdCallback : ISendMessageCallback  
        {  
            public const string HeaderName = "InstanceIdHeader";  
            public const string HeaderNS = "http://Microsoft.Samples.AccessingOperationContext";  
    
            public Guid InstanceId { get; set; }  
    
            public void OnSendMessage(System.ServiceModel.OperationContext operationContext)  
            {  
                operationContext.OutgoingMessageHeaders.Add(MessageHeader.CreateHeader(HeaderName, HeaderNS, this.InstanceId));  
            }  
        }  
    

    In diesem Code wird mit dem an die Methode übergebenen OperationContext der eingehenden Nachricht ein benutzerdefinierter Header hinzugefügt.

Implementieren einer clientseitigen systemeigenen Aktivität, um dem NativeActivityContext die clientseitige ISendMessageCallback-Implementierung hinzuzufügen

  1. Fügen Sie eine neue, von NativeActivity abgeleitete Klasse mit dem Namen SendInstanceIdScope hinzu.

  2. Fügen Sie lokale Variablen hinzu, um untergeordnete Aktivitäten, Variablen, den aktuellen Aktivitätsindex und einen CompletionCallback-Rückruf zu verfolgen.

    public sealed class SendInstanceIdScope : NativeActivity  
        {  
            Collection<Activity> children;  
            Collection<Variable> variables;  
            Variable<int> currentIndex;  
            CompletionCallback onChildComplete;  
    }  
    
  3. Implementieren des Konstruktors

    public SendInstanceIdScope()  
                : base()  
            {  
                this.children = new Collection<Activity>();  
                this.variables = new Collection<Variable>();  
                this.currentIndex = new Variable<int>();  
            }  
    
  4. Implementieren Sie die Activities-Eigenschaft und die Variables-Eigenschaft.

    public Collection<Activity> Activities  
    {  
         get { return this.children; }  
    }  
    
    public Collection<Variable> Variables  
    {  
        get { return this.variables; }  
    }  
    
  5. Überschreiben Sie CacheMetadata.

    protected override void CacheMetadata(NativeActivityMetadata metadata)  
    {  
        //call base.CacheMetadata to add the Activities and Variables to this activity's metadata  
        base.CacheMetadata(metadata);  
        //add the private implementation variable: currentIndex   
        metadata.AddImplementationVariable(this.currentIndex);  
    }  
    
  6. Überschreiben Sie Execute.

    protected override void Execute(  
                NativeActivityContext context)  
            {  
                context.Properties.Add("SendInstanceIdCallback", new SendInstanceIdCallback() { InstanceId = context.WorkflowInstanceId });  
                InternalExecute(context, null);  
            }  
    
            void InternalExecute(NativeActivityContext context, ActivityInstance instance)  
            {  
                //grab the index of the current Activity  
                int currentActivityIndex = this.currentIndex.Get(context);  
                if (currentActivityIndex == Activities.Count)  
                {  
                    //if the currentActivityIndex is equal to the count of MySequence's Activities  
                    //MySequence is complete  
                    return;  
                }  
    
                if (this.onChildComplete == null)  
                {  
                    //on completion of the current child, have the runtime call back on this method  
                    this.onChildComplete = new CompletionCallback(InternalExecute);  
                }  
    
                //grab the next Activity in MySequence.Activities and schedule it  
                Activity nextChild = Activities[currentActivityIndex];  
                context.ScheduleActivity(nextChild, this.onChildComplete);  
    
                //increment the currentIndex  
                this.currentIndex.Set(context, ++currentActivityIndex);  
            }  
    protected override void Execute(  
                NativeActivityContext context)  
            {  
                context.Properties.Add("ReceiveInstanceIdCallback", new ReceiveInstanceIdCallback());  
                InternalExecute(context, null);  
            }  
    
            void InternalExecute(NativeActivityContext context, ActivityInstance instance)  
            {  
                //grab the index of the current Activity  
                int currentActivityIndex = this.currentIndex.Get(context);  
                if (currentActivityIndex == Activities.Count)  
                {  
                    //if the currentActivityIndex is equal to the count of MySequence's Activities  
                    //MySequence is complete  
                    return;  
                }  
    
                if (this.onChildComplete == null)  
                {  
                    //on completion of the current child, have the runtime call back on this method  
                    this.onChildComplete = new CompletionCallback(InternalExecute);  
                }  
    
                //grab the next Activity in MySequence.Activities and schedule it  
                Activity nextChild = Activities[currentActivityIndex];  
                context.ScheduleActivity(nextChild, this.onChildComplete);  
    
                //increment the currentIndex  
                this.currentIndex.Set(context, ++currentActivityIndex);  
            }  
    

Implementieren eines Workflowclients

  1. Erstellen Sie ein neues Konsolenanwendungsprojekt mit dem Namen Client.

  2. Fügen Sie Verweise auf die folgenden Assemblys hinzu:

    1. System.Activities

    2. System.ServiceModel

    3. System.ServiceModel.Activities

  3. Öffnen Sie die generierte Datei Program.cs, und fügen Sie eine statische Methode mit dem Namen GetClientWorkflow hinzu, um den Clientworkflow zu erstellen.

    static Activity GetClientWorkflow()  
            {  
                Variable<string> echoString = new Variable<string>();  
    
                // Define the endpoint  
                Endpoint clientEndpoint = new Endpoint  
                {  
                    Binding = new BasicHttpBinding(),  
                    AddressUri = new Uri("http://localhost:8080/Service")  
                };  
    
                // Configure the Send activity used to send a message  
                Send echoRequest = new Send  
                {  
                    Endpoint = clientEndpoint,  
                    ServiceContractName = XName.Get("IService", "http://tempuri.org"),  
                    OperationName = "Echo",  
                    Content = new SendParametersContent()  
                    {  
                        Parameters = { { "echoString", new InArgument<string>("Hello, World") } }   
                    }  
                };  
    
                // Place the Send activity in a SendInstanceIdScope. This hooks up the ISendMessageCallback   
                // implementation to the client workflow.  
                return new SendInstanceIdScope  
                {  
                    Variables = { echoString },  
                    Activities =  
                    {                      
                        new CorrelationScope  
                        {  
                            Body = new Sequence  
                            {  
                                Activities =   
                                {  
                                    // Send the request message  
                                    echoRequest,  
    
                                   // Receive the reply from the service  
                                    new ReceiveReply  
                                    {  
                                        Request = echoRequest,  
                                        Content = new ReceiveParametersContent  
                                        {  
                                            Parameters = { { "result", new OutArgument<string>(echoString) } }  
                                        }  
                                    }  
                                }  
                            }  
                        },                      
                        new WriteLine { Text = new InArgument<string>( (e) => "Received Text: " + echoString.Get(e) ) },                      
                    }  
                };  
            }  
    
  4. Fügen Sie der Main()-Methode den folgenden Hostcode hinzu.

    static void Main(string[] args)  
    {  
       Activity workflow = GetClientWorkflow();  
       WorkflowInvoker.Invoke(workflow);  
       WorkflowInvoker.Invoke(workflow);  
       Console.WriteLine("Press [ENTER] to exit");  
       Console.ReadLine();  
    }  
    

Beispiel

Im Folgenden finden Sie eine vollständige Auflistung des in diesem Thema verwendeten Quellcodes.

// ReceiveInstanceIdScope.cs  
//----------------------------------------------------------------  
// Copyright (c) Microsoft Corporation.  All rights reserved.  
//----------------------------------------------------------------  

using System.Activities;  
using System.Collections.ObjectModel;  

namespace Microsoft.Samples.AccessingOperationContext.Service  
{  
    public sealed class ReceiveInstanceIdScope : NativeActivity  
    {  
        Collection<Activity> children;  
        Collection<Variable> variables;  
        Variable<int> currentIndex;  
        CompletionCallback onChildComplete;  

        public ReceiveInstanceIdScope()  
            : base()  
        {  
            this.children = new Collection<Activity>();  
            this.variables = new Collection<Variable>();  
            this.currentIndex = new Variable<int>();  
        }  

        public Collection<Activity> Activities  
        {  
            get  
            {  
                return this.children;  
            }  
        }  

        public Collection<Variable> Variables  
        {  
            get  
            {  
                return this.variables;  
            }  
        }  

        protected override void CacheMetadata(NativeActivityMetadata metadata)  
        {  
            //call base.CacheMetadata to add the Activities and Variables to this activity's metadata  
            base.CacheMetadata(metadata);  
            //add the private implementation variable: currentIndex   
            metadata.AddImplementationVariable(this.currentIndex);  
        }                     

        protected override void Execute(  
            NativeActivityContext context)  
        {  
            context.Properties.Add("ReceiveInstanceIdCallback", new ReceiveInstanceIdCallback());  
            InternalExecute(context, null);  
        }  

        void InternalExecute(NativeActivityContext context, ActivityInstance instance)  
        {  
            //grab the index of the current Activity  
            int currentActivityIndex = this.currentIndex.Get(context);  
            if (currentActivityIndex == Activities.Count)  
            {  
                //if the currentActivityIndex is equal to the count of MySequence's Activities  
                //MySequence is complete  
                return;  
            }  

            if (this.onChildComplete == null)  
            {  
                //on completion of the current child, have the runtime call back on this method  
                this.onChildComplete = new CompletionCallback(InternalExecute);  
            }  

            //grab the next Activity in MySequence.Activities and schedule it  
            Activity nextChild = Activities[currentActivityIndex];  
            context.ScheduleActivity(nextChild, this.onChildComplete);  

            //increment the currentIndex  
            this.currentIndex.Set(context, ++currentActivityIndex);  
        }  
    }  
}  
// ReceiveInstanceIdScope.cs  
//----------------------------------------------------------------  
// Copyright (c) Microsoft Corporation.  All rights reserved.  
//----------------------------------------------------------------  

using System;  
using System.ServiceModel;  
using System.ServiceModel.Activities;  

namespace Microsoft.Samples.AccessingOperationContext.Service  
{  
    class ReceiveInstanceIdCallback : IReceiveMessageCallback  
    {  
        public const string HeaderName = "InstanceIdHeader";  
        public const string HeaderNS = "http://Microsoft.Samples.AccessingOperationContext";  

        public void OnReceiveMessage(System.ServiceModel.OperationContext operationContext, System.Activities.ExecutionProperties activityExecutionProperties)  
        {              
            try  
            {  
                Guid instanceId = operationContext.IncomingMessageHeaders.GetHeader<Guid>(HeaderName, HeaderNS);  
                Console.WriteLine("Received a message from a workflow with instanceId = {0}", instanceId);  
            }  
            catch (MessageHeaderException)  
            {  
                Console.WriteLine("This message must not be from a workflow.");  
            }  
        }  
    }  
}  
// Service.cs  
//----------------------------------------------------------------  
// Copyright (c) Microsoft Corporation.  All rights reserved.  
//----------------------------------------------------------------  

using System;  
using System.Activities;  
using System.Activities.Statements;  
using System.ServiceModel;  
using System.ServiceModel.Activities;  
using System.Xml.Linq;  

namespace Microsoft.Samples.AccessingOperationContext.Service  
{      
    class Program  
    {  
        const string addr = "http://localhost:8080/Service";  
        static XName contract = XName.Get("IService", "http://tempuri.org");  

        static void Main(string[] args)  
        {  
            string addr = "http://localhost:8080/Service";  

            using (WorkflowServiceHost host = new WorkflowServiceHost(GetServiceWorkflow()))  
            {  
                host.AddServiceEndpoint(contract, new BasicHttpBinding(), addr);  

                host.Open();  
                Console.WriteLine("Service waiting at: " + addr);  
                Console.WriteLine("Press [ENTER] to exit");  
                Console.ReadLine();  
                host.Close();  
            }  

        }  

        static Activity GetServiceWorkflow()  
        {  
            Variable<string> echoString = new Variable<string>();  

            Receive echoRequest = new Receive  
            {  
                CanCreateInstance = true,  
                ServiceContractName = contract,  
                OperationName = "Echo",  
                Content = new ReceiveParametersContent()  
                {  
                    Parameters = { { "echoString", new OutArgument<string>(echoString) } }  
                }  
            };  

            return new ReceiveInstanceIdScope  
            {  
                Variables = { echoString },  
                Activities =  
                {  
                    echoRequest,  
                    new WriteLine { Text = new InArgument<string>( (e) => "Received: " + echoString.Get(e) ) },  
                    new SendReply  
                    {  
                        Request = echoRequest,  
                        Content = new SendParametersContent()  
                        {  
                            Parameters = { { "result", new InArgument<string>(echoString) } }   
                        }  
                    }  
                }  
            };  
        }  
    }  

}  
// SendInstanceIdCallback.cs  
//----------------------------------------------------------------  
// Copyright (c) Microsoft Corporation.  All rights reserved.  
//----------------------------------------------------------------  

using System;  
using System.ServiceModel.Activities;  
using System.ServiceModel.Channels;  

namespace Microsoft.Samples.AccessingOperationContext.Client  
{  
    class SendInstanceIdCallback : ISendMessageCallback  
    {  
        public const string HeaderName = "InstanceIdHeader";  
        public const string HeaderNS = "http://Microsoft.Samples.AccessingOperationContext";  

        public Guid InstanceId { get; set; }  

        public void OnSendMessage(System.ServiceModel.OperationContext operationContext)  
        {  
            operationContext.OutgoingMessageHeaders.Add(MessageHeader.CreateHeader(HeaderName, HeaderNS, this.InstanceId));  
        }  
    }  
}  
// SendInstanceIdScope.cs  
//----------------------------------------------------------------  
// Copyright (c) Microsoft Corporation.  All rights reserved.  
//----------------------------------------------------------------  

using System.Activities;  
using System.Collections.ObjectModel;  

namespace Microsoft.Samples.AccessingOperationContext.Client  
{  
    public sealed class SendInstanceIdScope : NativeActivity  
    {  
        Collection<Activity> children;  
        Collection<Variable> variables;  
        Variable<int> currentIndex;  
        CompletionCallback onChildComplete;  

        public SendInstanceIdScope()  
            : base()  
        {  
            this.children = new Collection<Activity>();  
            this.variables = new Collection<Variable>();  
            this.currentIndex = new Variable<int>();  
        }  

        public Collection<Activity> Activities  
        {  
            get  
            {  
                return this.children;  
            }  
        }  

        public Collection<Variable> Variables  
        {  
            get  
            {  
                return this.variables;  
            }  
        }  

        protected override void CacheMetadata(NativeActivityMetadata metadata)  
        {  
            //call base.CacheMetadata to add the Activities and Variables to this activity's metadata  
            base.CacheMetadata(metadata);  
            //add the private implementation variable: currentIndex   
            metadata.AddImplementationVariable(this.currentIndex);  
        }  

        protected override void Execute(  
            NativeActivityContext context)  
        {  
            context.Properties.Add("SendInstanceIdCallback", new SendInstanceIdCallback() { InstanceId = context.WorkflowInstanceId });  
            InternalExecute(context, null);  
        }  

        void InternalExecute(NativeActivityContext context, ActivityInstance instance)  
        {  
            //grab the index of the current Activity  
            int currentActivityIndex = this.currentIndex.Get(context);  
            if (currentActivityIndex == Activities.Count)  
            {  
                //if the currentActivityIndex is equal to the count of MySequence's Activities  
                //MySequence is complete  
                return;  
            }  

            if (this.onChildComplete == null)  
            {  
                //on completion of the current child, have the runtime call back on this method  
                this.onChildComplete = new CompletionCallback(InternalExecute);  
            }  

            //grab the next Activity in MySequence.Activities and schedule it  
            Activity nextChild = Activities[currentActivityIndex];  
            context.ScheduleActivity(nextChild, this.onChildComplete);  

            //increment the currentIndex  
            this.currentIndex.Set(context, ++currentActivityIndex);  
        }  
    }  
}  
// Client.cs  
//----------------------------------------------------------------  
// Copyright (c) Microsoft Corporation.  All rights reserved.  
//----------------------------------------------------------------  

using System;  
using System.Activities;  
using System.Activities.Statements;  
using System.ServiceModel;  
using System.ServiceModel.Activities;  
using System.Xml.Linq;  

namespace Microsoft.Samples.AccessingOperationContext.Client  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            Activity workflow = GetClientWorkflow();  
            WorkflowInvoker.Invoke(workflow);  
            WorkflowInvoker.Invoke(workflow);  
            Console.WriteLine("Press [ENTER] to exit");  
            Console.ReadLine();  
        }  

        static Activity GetClientWorkflow()  
        {  
            Variable<string> echoString = new Variable<string>();  

            Endpoint clientEndpoint = new Endpoint  
            {  
                Binding = new BasicHttpBinding(),  
                AddressUri = new Uri("http://localhost:8080/Service")  
            };  

            Send echoRequest = new Send  
            {  
                Endpoint = clientEndpoint,  
                ServiceContractName = XName.Get("IService", "http://tempuri.org"),  
                OperationName = "Echo",  
                Content = new SendParametersContent()  
                {  
                    Parameters = { { "echoString", new InArgument<string>("Hello, World") } }   
                }  
            };  

            return new SendInstanceIdScope  
            {  
                Variables = { echoString },  
                Activities =  
                {                      
                    new CorrelationScope  
                    {  
                        Body = new Sequence  
                        {  
                            Activities =   
                            {  
                                echoRequest,  
                                new ReceiveReply  
                                {  
                                    Request = echoRequest,  
                                    Content = new ReceiveParametersContent  
                                    {  
                                        Parameters = { { "result", new OutArgument<string>(echoString) } }  
                                    }  
                                }  
                            }  
                        }  
                    },                      
                    new WriteLine { Text = new InArgument<string>( (e) => "Received Text: " + echoString.Get(e) ) },                      
                }  
            };  
        }  
    }  
}  

Optionale Kommentare.

Siehe auch

Workflowdienste
Zugreifen auf OperationContext
Erstellen von Workflows, Aktivitäten und Ausdrücken mit imperativem Code