Powerful .NET Technologies

I have written this post to address several technologies available to dot net developers that I consider  exciting to work with. I will dwell into the details of each of the technologies in future posts. I do recommend that non dot net developers try to understand the rationale behind the technology and possibly find you dev environment equivalent or better still pioneer your own projects to add these into your platform. In this post I will give an introduction to four technologies in dot net namely, Language Integrated Query(LINQ), Windows Communication Foundation(WFC), Windows Presentation Foundation(WPF) and Windows Workflow Foundation WWF. I will go right ahead and give you a feel of what each is all about

LINQ

LINQ is Microsoft’s technology to provide a language-level support mechanism for querying data of all types. These types include in-memory arrays and collections, databases, XML documents, and more. Virtually any data store would make a good candidate for supporting LINQ queries. This includes databases, Microsoft’s Active Directory, the registry, the file system, an Excel file, and so on. LINQ offers a compact, expressive, and intelligible syntax for manipulating data. The real value of LINQ comes from its ability to apply the same query to an SQL database, a Dataset, an array of objects in memory or an XML file. LINQ requires the presence of specific language extensions.

LINQ uses an SQL-like syntax to make query expressions well beyond the capabilities of embedded SQL as implemented in programming languages. That's because embedded SQL uses a simplified, streamlined syntax to add SQL statements to other programming languages, where there's no attempt to integrate such statements into the native syntax and typing mechanisms. Thus, you can't invoke native language structures such as functions in embedded SQL statements, as you can using LINQ, because it is implemented to use native syntax, structures, and typing mechanisms. Furthermore, LINQ may be used to access all kinds of data, whereas embedded SQL is limited to addressing only databases that can handle SQL queries. Here is an example of using linq to SQL

 WCF

Web services, which uses standard protocols for application-to-application communication, have changed software development. The benefits of the changes in Web services should be reflected in the tools and technologies that developers use. Windows Communication Foundation  is designed to offer a manageable approach to distributed computing, broad interoperability, and direct support for service orientation.

WCF simplifies development of connected applications through a new service-oriented programming model. WCF supports many styles of distributed application development by providing a layered architecture. At its base, the WCF channel architecture provides asynchronous, untyped message-passing primitives. Built on top of this base are protocol facilities for secure, reliable, transacted data exchange and broad choice of transport and encoding options.

The typed programming model (called the service model) is designed to ease the development of distributed applications The service model features a straightforward mapping of Web services concepts to those of the .NET Framework common language runtime (CLR), including flexible and extensible mapping of messages to service implementations in languages such as Visual C# or Visual Basic. It includes serialization facilities that enable loose coupling and versioning

With WCF, distributed applications are much easier to implement, due to the following facts

           Because WCF can communicate using Web services, interoperability with other platforms that also support SOAP, such as the leading J2EE-based application servers, is straightforward.

• You can also configure and extend WCF to communicate with Web services using messages not based on SOAP, for example, simple XML formats like RSS. 
• Performance is of paramount concern for most businesses. WCF is developed with the goal of being one of the fastest distributed application platform developed by Microsoft
• To allow optimal performance when both parties in a communication are built on WCF, the wire encoding used in this case is an optimized binary version of an XML Information Set. Messages still conform to the data structure of a SOAP message, but their encoding uses a binary representation of that data structure rather than the standard angle-brackets-and-text format of the XML 1.0 text encoding. Using this option makes sense for communicating with the call center client application, because it is also built on WCF, and performance is an important concern.
• Managing object lifetimes, defining distributed transactions, and other aspects of Enterprise Services are now provided by WCF. They are available to any WCF-based application, which means that your application can use them with any of the other applications it communicates with.
• Because it supports a large set of the WS-* specifications, WCF helps provide reliability, security, and transactions when communicating with any platform that also supports these specifications.
• The WCF option for queued messaging, built on Message Queuing, allows applications to use persistent queuing without using another set of application programming interfaces.

The result of this unification is greater functionality and significantly reduced complexity.

  WWF

Most businesses require processes to function properly. There are different types of processes. Some processes are human-intensive, others machine-intensive, and the last type is a combination of the first two. Some examples of business processes are payroll, new product introductions, new employee hiring, etc. In most cases, these business processes require intervention from multiple entities and thus, are normally long running.  Workflow is one of the mechanisms used by businesses to express their business processes as a series of self-contained activities. Business Process Management (BPM) systems provided an environment for developers to create, execute, and manage workflows. These workflows are normally expressed using Finite State Machine (FSM), Unified Modeling Language (UML) Activity Diagrams, UML Swim Lanes, or Flow Charts. WF technology complements the .NET Framework with a group of workflow-related components that allow developers the ability to define, compile, instantiate, debug, and track workflows. This technology will become part of WinFX together with Windows Presentation Foundation, and Windows Communication Foundation.

WF workflows are composed using activities. Activities represent discreet pieces of functionality that are used to run specific business activities. There are two types of activities: composite and individual activities. Composite activities are used to express control statements (i.e., While, For, If-Then-Else, Case, etc.) and for grouping activities that share behavior (i.e., Sequences, Conditioned Activity Groups, etc.). Also, these activities are used to develop reusable sub-processes or sub-workflows. On the opposite side, individual activities provide a mechanism for expressing single pieces of work that need to be executed in the same step in the workflow.The workflow run time is responsible for taking workflow definitions and instantiating them. The life cycle of the workflow instances are managed by the workflow runtime. It is responsible for creating, executing, threading, persisting, tracking, communicating execution events, and coordinating transactions. These functions are managed by the workflow run time via services. There is a set of default services that the run time uses to manage all of its workflow instances, threading, transactions, tracking, state management, etc. Application developers responsible for integrating workflows into their existing applications can overwrite these services. Using this service model, developers are able to expose their existing hosting infrastructure to the workflow library. The framework provides a set of out-of-box services that allow developers to quickly start using the environment without worrying about having to write complicated code.

WPF 

Windows Presentation Foundation is a development tool for Web applications and rich client applications. With WPF, developers can use XAML, the Extensible Application Markup Language, to create custom controls, graphics, 3D images and animations that are not available in traditional HTML implementations.