Web Parts are building blocks of pages in SharePoint sites. Users of SharePoint can make use of these building blocks to determine what should be displayed on a specific page in SharePoint site. Both WSS and MOSS give us many out-of-box web parts. Developers can create custom web parts either using classes from scratch or can extend existing web parts using Visual Studio.
Choosing Between ASP.NET and SharePoint Web Parts
In general, you should design new Web Parts that inherit from the ASP.NET 2.0 WebPart class. ASP.NET Web Parts have description file names that use the .webpart extension. ASP.NET Web Parts provide the greatest flexibility and compatibility with Web sites that are not tightly coupled with Windows SharePoint Services.
Windows SharePoint Services 3.0 Web Parts provide backward compatibility with Windows SharePoint Services 2.0. SharePoint Web Parts have description file names that use the .dwp extension. SharePoint Web Parts include additional functionality but can be used only in a SharePoint site. Following is a list of the added features of SharePoint Web Parts.
- Cross-page connections in SharePoint sites
- Connections between Web Parts that are outside of a Web Part zone
- Client-side connections using the Web Part Page Services Component
- Web Part data caching
- Asynchronous processing using Web Part work items