Features of .NET
Language support
.NET is language independent and can use any language once a mapping exists from that language to MSIL. At the time of this writing, several third-party vendors have produced language compilers that target the CLR; examples include NetCobol from Fujitsu, and Visual Perl and Visual Python from ActiveState,.
Because all .NET languages share a common type system, developers can safely pass types written in one language to code written in another (even Strings from Visual Basic.NET to Visual C++.NET!). They can also use the unified Framework class libraries in any .NET language, saving them from having to learn how to work with many different implementations.
Standards support
Microsoft has long been criticised for tightly controlling its technologies. However, the company took a huge step forward when it submitted C# and the CLR to ECMA for ratification. On December 13, 2001, the ECMA General Assembly ratified the C# and CLR specifications into international standards, allowing others to participate in their evolution.
Tools support
Microsoft's long and successful development tools history continues with Visual Studio .NET, the single Integrated Development Environment (IDE) for building .NET applications, whether you're building Windows applications, Web applications, or XML Web services. With Visual Studio .NET, you can choose any .NET language. From the developer's viewpoint, applications are built using a single IDE. Visual Studio .NET boasts too many features to address here, but it's worth mentioning the new Server Explorer feature. With the Server Explorer, developers can access server resources (message queues, performance counters, data sources, and so on) in a drag-and-drop fashion without ever leaving Visual Studio .NET. Microsoft likes to think of this as "RAD for the server".
How does it work?
In a .NET application, SOAP uses XML to describe messages and transports them via HTTP. Web Services Description Language (WDSL) is a new specification to describe networked XML-based services -- Web services.
WDSL offers a simple way to describe the basic format of requests regardless of the underlying protocol (such as SOAP or XML) or encoding (such as Multi-purpose Internet Mail Extensions). WDSL is a key part of the effort of the Universal Description, Discovery and Integration (UDDI) initiative to provide directories and descriptions of online services for e-commerce.
Visual Studio.NET makes creating Web service client or server applications intuitive and easy. To build a Web service server for example, you use a Visual Studio.NET wizard to create your initial application. To expose a class method in the Visual Basic application you created as a Web service, you add the attribute "<Webmethod()>" as part of the function definition.
Once the XML Web service has been built, it can be invoked via HTTP using XML to pass data to and from the service. To use an XML Web service from Visual Studio.NET, all developers need to do is add a Web reference to the exposed Web service.