Microsoft Sharepoint Products and Technologies Resource Kit eBook

936 Part IX: Maintaining a Server in Windows SharePoint Services
Microsoft.SharePoint.WebControls Namespace
The Microsoft.SharePoint.WebControls namespace contains Microsoft ASP.NET
server controls that are used on site and list pages in a SharePoint site. This
namespace can be found in the Windows SharePoint Services assembly (in
Microsoft.SharePoint.dll). The major class, SPControl, provides methods for getting
or setting the context of requests and serves as the base class from which other
controls in this namespace derive.
In general, although the set of Web controls within the Microsoft.SharePoint
.WebControls namespace are used extensively in SharePoint Products and Technologies,
they are of very limited usefulness to a third-party developer. In this section,
the most interesting controls will be shown. If you want to find out more about the
other controls, the best approach would be to see how the controls are used in the
layouts .aspx files and experiment.
The SPControl Class
The SPControl class provides methods for getting or setting the context of the
request and serves as the base server control from which other controls in the
Microsoft.SharePoint.WebControls namespace derive. As such, SPControl is very
important when programming the Windows SharePoint Services object model.
The SPControl class can be used in a Web Part, in a custom Web service (in _vti
_bin), or in an ASPX page or a Web Application (in _layouts). The following code
uses the GetContextSite method to return the site collection that serves as the context
for the current HTTP request. It also uses the GetContextWeb method to return the
website that serves as the context for the current HTTP request. Finally, it shows
how to retrieve the top-level website from the current site collection.
SPSite siteCollection = SPControl.GetContextSite(Context);
SPWeb site = SPControl.GetContextWeb(Context);
SPWeb topLevelSite = SPControl.GetContextSite(Context).RootWeb;
The FormDigest Control Class
The FormDigest class inserts a security validation within the form of an .aspx
page. To make posts from a Web application that modifies the contents of the
database, you must include the FormDigest control in the form making the post.
The FormDigest control generates a security validation, or message digest, to help
prevent the type of attack whereby a user is tricked into posting data to the server
without knowing it. The security validation is specific to a user, a site, and a time
period, and it expires after a configurable amount of time. When the user requests
a page, the server returns the page with security validation inserted. When the
user then submits the form, the server verifies that the security validation has not
changed. If you want to do website or lower-level operations in your page, you
need to use the FormDigestol.