To simplify development of XML Web service client applications, Visual Studio provides Web references. Web references differ from traditional references and components; instead of referencing a component or a class library installed on the local computer, a Web reference provides access to a resource that is available using an Internet protocol such as SOAP or HTTP.

In practice, a Web reference is a generated proxy class that locally represents the exposed functionality of an XML Web service. The proxy class defines methods that represent the actual methods exposed by an XML Web service. When your application creates an instance of the proxy class, your application can call the XML Web service methods as if the XML Web service were a locally available component. For instructions on creating a Web reference, see How to: Add and Remove Web References.

Note:
To make XML Web services outside a firewall available to the Web browser, when creating the Web reference in Visual Studio, you must explicitly specify the address and port of your network's proxy server.

The programming language of a generated proxy class will be the same as the programming language of the Web service that the proxy class represents. If you create the proxy class independently of Visual Studio (for example, by using a .NET Framework tool), the programming language depends on which tool you use. For example, if you use WSDL.exe, you specify the programming language on the command line as either C# or Visual Basic. If you use SProxy.exe, the programming language is Visual C++. For more information, see Web Services Description Language Tool (Wsdl.exe).

At design time, the proxy class enables you to use statement completion for the XML Web service methods. At run time, a call to a method of the proxy object is processed and encoded as a SOAP request message. If the XML Web service does not support SOAP, the proxy class uses HTTP GET and POST. The message is then sent to the target Web Service for processing. If the service description defines a response message, the proxy object processes this message and returns a response to your application.