In a traditional imperative program language such as C#, if one wished to send/receive message to/from a remote location, one was expected to write a lot of code, have thorough knowledge of TCP/IP, HTTP, .Net Remoting, Web Service, and so on. Starting from .NET Framework 3.0, Microsoft launched WCF (Windows Communication Foundation). By using WCF, messaging has become an easy and flexible task. WF4 takes advantage of WCF and provides some out of the box messaging activities. In this chapter, we will focus on the built-in messaging activities shipped by WF4.
In the case of service host, though we can use the Local Web Development Server shipped with .NET Framework4.0 as the WCF host, I personally recommend the real IIS7.0 or IIS 7.5. For detailed IIS installation steps, we can refer to the documents from http://learn.iis.net/page.aspx/85/installing-iis-7/.
To make sure our application has permission to open a WCF HTTP port, we should run Visual Studio 2010 as administrator.