The requirement for a domain trust relationship depends on how a SharePoint Farm is configured, the SharePoint Farm could either reside in a perimeter network (or hosted environment), or the SharePoint Farm could be split between a perimeter network and the internal network.
In this post we will assume a simple SharePoint Extranet where a SharePoint Farm and an Active Directory are in a hosted environment, and resource from the local Corporate domain (domain.local) are needed in the hosted environment (domain.ext).
Delegate Controls are generic controls found in all of the out-of-the-box master pages in SharePoint, a Delegate Control provides the ability to dynamically render ASP.net controls (candidates) in master pages extending the functionality of SharePoint without the need to directly modify any of those master pages.
So Basically, a Delegate Control provides a “plug-in” framework making its child candidates (ASP.NET user Controls) pluggable and replaceable.
Some of the available delegate controls in the master pages are:
In this post we will take a look at using the AdditionalPageHead Delegate control to quickly add a jQuery reference in SharePoint master pages.