Re: Service Enabling Workflows

Jared Bienz — Tue, 16 Sep 2008 03:30:03 GMT

Very sorry to everyone who was not able to get the sample files. I've upload them again and updated the link. Right now the file system still says 'Pending' but I hope that will be resolved tomorrow.

Re: Service Enabling Workflows

Johannes Hofmeister — Wed, 03 Sep 2008 11:29:59 GMT

The link ist still broken but the example itself shouldn't be too complex.
The biggest problem is to route the the message from the Service Object to the UI Control. This has to be done by invoking a delegate on the form or the control itself, gently asking it do display someting for you. I usually do it with events exposed by the service class:

// IMessageService.cs:
[ExternalDataExchange]
public interface IMessageService
{
        void SendMessage(string message);
}

//MessageService.cs
public class MessageService : IMessageService
{
        public event EventHandler<MessageReceivedEventArgs> MessageReceived;
        public void SendMessage(string message)
        {
            if (MessageReceived != null)
                MessageReceived(this,
                    new MessageReceivedEventArgs(
                        WorkflowEnvironment.WorkflowInstanceId,
                        message));
        }
}

The EventArgs object for this Event is a simple class derived from ExternalDataEventArgs, that contains a string property for the message. To identify the sender the ExternalDataEventArgs Ctor always requires a Guid.

Now you can instantiate the service from the host application, then register to the MessageReceived Event. When received you can build a delegate that will be invoked on the form to change properties of the controls to display the message

// in form load:

ExternalDataExchangeService service = new ExternalDataExchangeService();
_runtime.AddService(service);
_messageService = new GuessingGameService();
service.AddService(_gameService);
_messageService.MessageReceived += new EventHandler<MessageReceivedEventArgs>(_messageService_MessageReceived);

// the delegate
        private delegate void UpdateDelegate();

        void _messageService_MessageReceived(object sender, MessageReceivedEventArgs e)
        {
            UpdateDelegate theDelegate = delegate()
            {
                lblMessage.Text = e.Message;
            };
            _instanceId = e.InstanceId;
            this.Invoke(theDelegate); // invokes the delegate on the form updating the control.
}

-----

As there has no example been distributed so far - link still broken - i decided to do it on my own, and i hope this helps. if your want my sample code (very similar to this) just message me.

Re: Service Enabling Workflows

Ronald Garlit — Thu, 31 Jul 2008 18:39:48 GMT

The link to the code for the Service Enabled Sample files does not work. Are they posted?

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