How do I program my WCF service in the given scenario? - wcf

Question

I am currently developing a C# Windows Form Application that I intend to let it interact with a server. The server will receive posting from a mobile application that I have developed and whenever a posting is received, my Windows Form Application should be notified and give me a notification.
E.g. My mobile application sends an message over to my server. Once my server receives the message, my windows form application should display a new notification showing the content of the message received.
I am now starting to develop the WCF service and has reach the PostingService method and I am unsure of how I am able to continue to program the service to work the way I wan as stated above.
public class PostingService : IPostingService
{
public void NotifyAboutPosting(Posting post)
{
// do something with post here
}
}
and after I program the service, how do I test the service by, I dunno? uploading a fake post to see if the services works or whatsoever , meaning a dummy test. thanks !
EDIT
for my main method, the code are as follows ,
Uri baseAddress = new Uri("http://localhost/");
ServiceHost selfHost = new ServiceHost(typeof(IPostingService), baseAddress);
try
{
selfHost.AddServiceEndpoint(typeof(IPostingService),new WSHttpBinding(), "Posting");
ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
selfHost.Description.Behaviors.Add(smb);
selfHost.Open();
Console.WriteLine("The service is ready.");
Console.WriteLine("Press <ENTER> to terminate service.");
Console.WriteLine();
Console.ReadLine();
selfHost.Close();
}
catch (CommunicationException ce)
{
Console.WriteLine("An exception occurred: {0}", ce.Message);
selfHost.Abort();
}
basically I just followed through the tutorial given by MSDN WCF getting started tutorial. not sure if this is really the correct way to do it for the type of implementation that I want.

Answer 1

Well, your WCF service can do anything you want - so what do you really want it to do??
Your posting server gets a new message from a mobile device, and then calls this WCF service class in your Winforms app. What do you want to happen here and now??
One thing to keep in mind: the WCF service class receiving the message and the Winforms app might be running on different threads; if that's the case, you cannot just update e.g. UI elements on your Winforms UI from the service code (you need to use some synchronization methods). But that depends on your exact way of creating and opening the ServiceHost in your Winforms app.
Update: if you put your code to create and initialize your ServiceHost into the main application form (see Service Synchronization Context on CodeIdol for a sample on how to do this), then you could probably just do:
public class PostingService : IPostingService
{
public void NotifyAboutPosting(Posting post)
{
MessageBox.Show(post.Title, post.Message,
MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
assuming your Posting class has both a .Title and a .Message string property...

Answer 2

1) PostingService assembly (class-library project)
Interface: IPostingService.cs
using System;
using System.ServiceModel;
namespace PostingService
{
[ServiceContract]
public interface IPostingService
{
[OperationContract]
void NotifyAboutPosting(Posting posting);
}
}
Implementation: PostingService.cs
using System;
using System.Windows.Forms;
namespace PostingService
{
public class PostingService : IPostingService
{
public void NotifyAboutPosting(Posting posting)
{
MessageBox.Show(posting.Message, posting.Title, MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
}
DataContract: Posting.cs
using System;
using System.Runtime.Serialization;
namespace PostingService
{
[DataContract]
public class Posting
{
[DataMember]
public int ID { get; set; }
[DataMember]
public string Title { get; set; }
[DataMember]
public string Message { get; set; }
}
}
2) Your Winforms app (Winforms application project)
Must reference the service assembly (since it needs the service contract and the data contract class)
Main Form of your app: Form1.cs
using System;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.Windows.Forms;
using PostingService; // your class library from above
namespace WinformsApp
{
public partial class Form1 : Form
{
private ServiceHost _host = null;
public Form1()
{
InitializeComponent();
// IMPORTANT: here you need the **SERVICE IMPLEMENTATION CLASS** in the typeof() (*NOT* the interface!)
_host = new ServiceHost(typeof(PostingService), new Uri("http://localhost:8888/PostingService"));
ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
_host.Description.Behaviors.Add(smb);
_host.Open();
label2.Text = "Service up and running (http://localhost:8888/PostingService)";
}
protected override void OnFormClosed(FormClosedEventArgs e)
{
_host.Close();
base.OnFormClosed(e);
}
}
}
3) Run your Winforms app - now that service is up and running and ready to be notified.
4) Launch WCF Test Client (that's what your "posting server" will be doing later on)
4a) File > Add Service - type in http://localhost:8888/PostingService - should find your service
4b) if found: enter some values into the properties for the "Posting" class (an ID, title, message)
4c) Click "Invoke" - your service should now be called, a dialog pop (message box) should pop up with the title and message you've defined

Answer 3

Perhaps WCF callbacks might meet your requirements:
What You Need To Know About One-Way Calls, Callbacks, And Events