WCF (Windows Communication Foundation) services can be hosted in different environments:

• in IIS launched as a web service
• in WAS running e.g. as a Windows Service
• self hosted in any kind of application

 

Self hosting is quite simple as the following sample code illustrates.
For self hosted applications the host application needs to be started before a client can access the service.
WCF services hosted in IIS are launched when a client application accesses the web service URL.

 

C# Sample code of a WCF Host Application

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Windows.Forms;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.ServiceModel.Dispatcher;

namespace WCFHost
{
   public partial class Form1 : Form
   {
      ServiceHost serviceHost = null;

      public Form1()
      {
           InitializeComponent();
      }

      private void Form1_Load(object sender, EventArgs e)
      {
           try
           {
               // Create a ServiceHost for the XML DA service
               serviceHost = new ServiceHost(typeof(opcxml.OpcXmlDA));
               // Open the ServiceHost to create listeners and start listening for messages.
               serviceHost.Open();

               EventLog.WriteEntry("WCFselfHost", "The service is now available", EventLogEntryType.Information);

               tbInfo.Text = "The service is now available.\r\nThe configured Endpoint Listeners are:";
               foreach (ChannelDispatcher cd in serviceHost.ChannelDispatchers)
               {
                  foreach (EndpointDispatcher epd in cd.Endpoints)
                  {
                     tbInfo.Text += "\r\n    " + epd.EndpointAddress.Uri.AbsoluteUri;
                  }

               }
         }
         catch (Exception ex)
         {
            tbInfo.Text = ex.Message;
            if(serviceHost !=null)
               serviceHost.Abort();
         }
      }

      //---------------------------------------------------------
      void Form1_FormClosing(object sender, System.Windows.Forms.FormClosingEventArgs e)
      {
         if (serviceHost != null)
         {
            serviceHost.Close();
            serviceHost.Abort();
         }
      }

   }
}