Introduction

Web Services provide a new level of interaction to all kinds of applications. The ability to access and use a remote Web service to perform a function within an application enables programmers to quickly deliver a more sophisticated applications in less time. The programmer no longer has to create and maintain all functions of the application. Reusability is also greatly enhanced by creating multiple Web services that perform functions in multiple applications, thus freeing up time and resources to work on other aspects of specific projects. See Figure 1.1, which shows a graphical representation of this process.

Figure 1.1: Where Do Web Services Fit In?

In this chapter we will be looking at a simple Hello World Web Service delivered via ASP. NET. This Web Service example can be accessed by any application that can handle Simple Object Access Protocol (SOAP).

Web Services function primarily through XML in order to pass information back and forth through the Hypertext Transfer Protocol (HTTP). Web Services are a vital part of what the .NET Framework offers to programmers. XML-based data transfer is realized, enabling primitive types, enumerations, and even classes to be passed through Web Services to the application performing the request. This brings a whole new level of reusability to an application. XML is the backbone from which the whole Framework is built. The user interface (UI) can be created by applying Extensible Stylesheet Language Transformations (XSLTs) or by loading the data into DataSets and binding to Web Controls. Having...