Beginning ASP.NET 4.5 in CSharp and VB Opsylum

Using Web Services and Page Methods in Ajax Websites x 369
The web services in the Planet Wrox project will only be used to have a client page in the browser
talk to the server and exchange data. So, in this site, both the server and the client are in the same
web project—one executes at the client (the JavaScript that calls the web server), and the other lives
at the server (the web service itself). From a security point of view, this is the easiest solution because
both parts trust each other.
If you want your client-side pages to talk to a web service on a different domain, you could host
a service on your own site that calls the remote web service. The client browser then calls your
service, which in turns calls the remote service. This scenario falls outside the scope of this chapter,
though.
You see this WCF theory in practice in the following exercise.
Creating Web Services
Creating WCF services with VS is pretty easy. Just as with all the other document types, VS comes
with a template for a WCF service. You add the service to the site using the Add New Item dialog
box. You then modify the service code to suit your requirements. Next, you register the service in a
ScriptManager or ScriptManagerProxy and then you’re ready to call it from a client web page.
VS comes with a few different templates to create a WCF service. To create one that’s callable
from a website, you use the AJAX-enabled WCF Service template. When you add a service based
on this template, VS adds the necessary configuration code to allow calling this service from a
web page to the Web.config file for you. In addition, the coding model of this service is a bit
easier than the standard WCF Service template because it stores all the code in a single class
and file.
TRY IT OUT
Creating a Web Service
In this exercise you create a simple “Hello World” web service. This service accepts your name as an
input parameter and returns a friendly, personalized greeting. There’s not much real-world usage for
this exact web service, but because of the simplicity in the service itself, it’s easy for you to focus on the
underlying concepts.
1. Create a new folder called WebServices in the root of your site to group all web services in a
single folder. This is not required, but helps in organizing your site.
2. Next, right-click this new folder and choose Add Í Add New Item. Click the AJAX-enabled
WCF Service item. Because the list of templates can be quite long, you can quickly find the
right item by searching for WCF in the search box in the top-right corner of the Add New Item
dialog box.
Make sure that you click the item for your programming language, and call the service
NameService, as shown in Figure 10-6.