Summary

This chapter has been a brief look at Web Services and how they can be used to extend the reach of applications. This is already happening, with organizations such as Amazon.com having Web Services allowing access to its catalog and purchasing system, giving third parties the opportunity to integrate their users' experience with that of Amazon.com.

We started the chapter with a quick description of the protocols used in Web Services, before moving on to see how Web Services can easily be created and exposed from ASP.NET applications. You saw that even though Web Services have no user interface, ASP.NET dynamically creates a help page allowing you to both examine the SOAP packets used to communicate with the service and test the service.

You then saw how to use Web Services, seeing that once a reference to the service has been established, the service appears like any other class, with callable methods. You saw that the proxy object created by Visual Studio 2005 supports both synchronous and asynchronous calls, with the latter providing a simple event that is raised when the service call has completed. This eases the use of asynchronous services, providing increased performance for consumers.

You then saw how you can control the data serialization process, looking at simple schemes such as attributing the types in classes, and manually serializing the class and providing your own schema. This technique gives you more control over the layout of the XML and schema, which is useful when dealing with fixed schemas already in existence.

Finally, you saw how the Web Services Enhancements provide a simple toolkit for adding security to Web Services. Although this is an additional download, it integrates with Visual Studio 2005, providing a declarative way of stating security policies to use with Web Services. WSE is also an established standard, with wide third-party support, aiding interoperability.

This book has covered a lot of ground, and we hope that you've found it useful. We've endeavored to live up to the 'illustrated' title, showing practical topics and common scenarios. We've also provided links for you to further expand your knowledge, should a particular topic prove more interesting. While it would have been great to cover more topics in more detail, ASP.NET has become so large that this really isn't possible in a single book. ASP.NET 2.0 was a major upgrade to the technology, and improvements are still happening. Since ASP.NET 2.0 was released, several Visual Studio add-ins have been supplied by the ASP.NET team, and client-side scripting technologies are showing signs of a revival that will see even more exciting additions to the product. Keep an eye on the ASP.NET web site at http://www.asp.net/ for all the cool news.