Programming WCF Services, 2nd Edition

Client-Side Programming

To invoke operations on a service, a client first needs to import the service contract to the client's native representation. If the client uses WCF, the common way of invoking operations is to use a proxy. The proxy is a CLR class that exposes a single CLR interface representing the service contract. Note that if the service supports several contracts (over at least as many endpoints), the client needs one proxy per contract type. The proxy provides the same operations as the service's contract, but also has additional methods for managing the proxy lifecycle and the connection to the service. The proxy completely encapsulates every aspect of the service: its location, its implementation technology and runtime platform, and the communication transport.

Generating the Proxy

You can use Visual Studio 2008 to import the service metadata and generate a proxy. If the service is self-hosted outside the solution, first launch the service and then select Add Service Reference from the client project's context menu. If the service is self-hosted in the same solution, first launch it without the debugger, and then select the Add Service Reference option from the context menu.

If the service is hosted in IIS 5/6 or WAS, there is no need to prelaunch the service; simply select Add Service Reference from the client project's context menu, and Visual Studio will bring up the Add Service Reference dialog, shown in Figure 1-9.

Figure 1-9. Generating a proxy using Visual Studio ...