Beginning Web Development, Silverlight, and ASP.NET AJAX

110
CHAPTER 5 ■ ASP.NET WEB SERVICES
The code in Listing 5-1 defines a class called Service. As you recall, the WebService
directive specified this class when it defined Service as the implementing class of the web
service logic.
The class is decorated with a couple of attributes. The first one ([WebService
(Namespace = "http://tempuri.org/")]) sets the namespace for your web service. You
should use a namespace when publishing your web service to distinguish it from other
services on the Web that may have the same name and to help reinforce your branding.
The second attribute ensures that your web service conforms to the WS-I basic profile.
The WS-I is a group of technology vendors, including Microsoft, who have developed
a set of rules called profiles to define how a web service should work. Profiles ensure that
different technologies won’t prevent web service clients and servers from communicating
with each other. The most common profile is called the Basic Profile. In its simplest
sense, the Basic Profile ensures that only data that is common to all technology platforms
can be exposed via a web service. Thus, to conform to the Basic Profile, a Java web service
cannot expose a Java-specific data type such as Vector. Conversely, a .NET-based service
cannot expose a .NET-specific data type such as DataSet. The WebServiceBinding attribute
([WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]) forces your web service
to conform to the Basic Profile version 1.1, thus ensuring interoperability.
Your final responsibility when developing a web service in ASP.NET is to define which
methods your class will export by using the WebMethod attribute. Only the methods that
have been attributed with WebMethod will be exposed to the outside world.
Running Your Web Service
When you view the running web service in the browser, you’ll see the ASP.NET web service
description page. From here, if you select methods from the bulleted list, you can
inspect and test the web methods that have been exposed using the WebMethod attribute.
Should those methods require input parameters, the test page for that method will provide
text boxes for you to enter the parameter values. You can see the test page for the
default Hello World web service in Figure 5-3.