SharePoint provide a instrument that allow developers to modify
out of the box functionality in page, with no need for modify the
pages that approach with SharePoint. This instrument is provide
with delegate controls.
A delegate control define a area in an aspx page that allows
the satisfied to be replace with our custom satisfied. This custom
satisfied is created via a SharePoint feature, and when deploy and
activate, replaces the standard happy at runtime.
By declaring a control as an part in a characteristic and
giving it a main concern through the Sequence quality of the
Control part, SharePoint select the affirmed control candidate and
instantiates it as a child of the delegate control. At run time,
this delegate control accepts the union of control basics declared
at the member of staff serving at table farm, Web request, site
collection, and Web site levels.
The control that has the lowest series number is added to the
manage tree from side to side the Delegate Control.
Delegate controls for which the Allow Multiple Controls
property generation true can host more than one child control.
If there are various delegate control candidate, they are all
added as children at runtime in the order specified by the Sequence
quality. For example, by default the Allow Multiple wheel property
is used in the extra Page Head delegate control to allow multiple
child controls to be extra to any page that contain the delegate
control.