This print for content only-size & color not accurate 7" X 9-1/4" / casebound / malloy

■

I N T R O D U C I N G  W I N D O W S   C O M M U N I C AT I O N   F O U N D AT I O N

870

8849CH25.qxd  10/16/07  10:51 AM  Page 870

---

Figure 25-1.

XML web services allow for a very high degree of interoperability.

By way of a quick example, assume you have authored the following programming logic in a

new file named HelloWebService.asmx (*.asmx is the default file extension for a .NET XML web serv-

ice file). Once you have done so, save it into C:\HelloWebService.

<%@ WebService Language="C#" %>

using System;

using System.Web.Services;

public class HelloWebService

{

[WebMethod]

public string HelloWorld()

{

return "Hello World";

}

}

While this simple service is hardly doing anything terribly useful, notice that the file opens with

the WebService directive, which is used to specify which .NET programming language is used in the

file, and the name of the class type representing the service. Beyond this, the only point of interest is

that the HelloWorld() method has been decorated with the [WebMethod] attribute. In many cases,

this is all you need to do to expose a method to external callers via HTTP. Finally, notice that you do

not need to do anything special to encode the return value into XML, as this is done automatically

by the runtime. 

If you wish to test this web service, simply open up a Visual Studio 2008 command prompt and

enter the following command (if you’d like to see each option you can use with this development

web server, simply enter the -? argument):

webdev.webserver /port:8080 /path:"C:\HelloWebService"

C H A P T E R   2 5