Smart Client Applications

Just read this blog entry about Smart Client technology and an architect's dilemma to choose an appropriate client UI technology. I had blogged about Smart Clients earlier here. 

In the blog posts, Philip discusses the scenarios where-in a thin web-based client makes sense. For SmartClient, he says that 'offline' applications are the best fit where it makes sense to use a thick client. I feel there is another strong reason why one would want to select Smart Client UI - a rich user experience. Even with cutting edge Ajax solutions, it is impossible to get the same look and feel of a desktop application over a browser.  We also have powerful WinForms/SmartClient third-party controls such as those from Infragistics that enable you to slice-n-dice thousands of records in a grid. Such raw power is not available over a web interface.

Other important point raised by Philip was the security aspect of Smart Client applications. How would we protect the client code and data from being compromised? Possible solutions:

- Encrypt all data
- Obfuscate the dlls

- Resolve data concurrency errors and database replication errors.

Smart clients....Has the pendulum swung back?

Before the emergence of the 'web' most of the UI development was 'rich-thick-client' based on MS platforms such as VB, MFC, etc. VB development enjoyed a lot of popularity because of the component based model and the ready availability of rich UI widgets and development environments such as Visual Studio.
Such rich clients suffered from 2 major drawbacks: DLL hell and application upgrade/deployment.
Maintaining the correct version of the application across all clients distributed across locations was a big pain.

To address this problem, many thick clients were migrated to a web-based UI with a centralized server and repository. But this 'silver bullet' again had 2 main drawbacks - the user experience was nowhere close to that of a rich client. Even with the emergence of RIA (Rich Internet Applications) and AJAX, those applications requiring tons of data input and fast keyboard based navigation across screens, the web UI offered serious limitations.

And it is here that .NET smart clients come into the picture. A .NET smart client has the following features:
- Uses the 'click once' platform feature to automatically update DLLs on the client machine. Thus deployment is no longer a problem.
- Smart clients build on .NET resolve the DLL hell problem using metadata versioning of assemblies.
- Smart clients can talk with webservices to obtain data and fulfill other business requirements.
- Smart clients can work in offline mode - offering either limited or full functionality.
- Smart clients can easily integrate with other applications on the desktop providing an integrated approach to the user.
- Using WPF, users can be given a rich user interface that they demand.