Microsoft Sharepoint Products and Technologies Resource Kit eBook

1122 Part XI: Upgrading and Migrating to SharePoint Products and Technologies
Custom Web Parts must derive from the Microsoft.SharePoint.WebPartPages.WebPart
base class. For more information about how to create a Web Part, see Part 10,
“Microsoft Office 2003 Integration with SharePoint Products and Technologies” and
the SharePoint Products and Technologies SDK. You can write custom Web Parts for
any of the following purposes:
■ Creating custom properties and using the Web Part infrastructure to display
them in the tool pane.
■ Creating custom Tool Parts in the tool pane.
■ Creating a base class for other Web Parts to extend. For example, to create a
collection of Web Parts with similar features and functionality, create a custom
base class from which multiple Web Parts can inherit. This reduces the overall
cost of developing and testing subsequent Web Parts.
■ Improving performance and scalability. A compiled custom Web Part runs
faster than a script.
■ Securing and controlling access to content within the Web Part. The built-in
Web Parts allow any users with appropriate permissions to change content and
alter Web Part functionality. With a custom Web Part, you can determine the
content or properties to display to users, regardless of their permissions.
■ Making your Web Part connectable by implementing one or more of the
defined Web Part Connection interfaces. This allows the custom Web Part to
provide or access data from other connectable Web Parts.
■ Interacting with the object models that are exposed in SharePoint Products and
Technologies. For example, you can create a custom Web Part to save documents
to a Windows SharePoint Services document library.
■ Controlling the cache for the Web Part by using built-in cache tools. For example,
you can use these tools to specify when to read, write, or invalidate the
Web Part cache.
■ Benefiting from a rich development environment with debugging features that
are provided by tools such as Visual Studio .NET.
■ Implementing proprietary code without disclosing the source code.
■ Controlling the implementation of the Web Part. For example, you can write a
custom server-side Web Part that connects to a back-end database, or you can
create a Web Part that is compatible with a broader range of Web browsers.
To successfully convert your dashboard Web Parts to the Web Part infrastructure,
you must understand the changes to properties, namespace, resource handling,
tokens, DDSC, and .dwp files that are described in the white paper “Converting
Dashboard Web Parts to the Web Part Infrastructure for Microsoft SharePoint Products
and Technologies,” mentioned earlier in this chapter, and the SDKs.