ASP.NET Page Life Cycle Events
The page life cycle events are :
PreInit
|
PreLoad
|
PreRender
|
Unload |
PreInit :
This is the initial
stage of the page means this is entry point
of page life cycle .
This checks for is PostBack that means first time the request is sent or the first
time page is processed. Dynamic controls are created in this event such as:
To Set master page dynamically.
Init:
In this Init Event
for the individual control is initialised first
and later the init for the page takes place. This event is used to initialize the control
properties i.e. Each control in the control collection is initialized.
InitComplete:
View State is turned on in this
event . Any changes made to the View State in this event are persisted even after
the next postback. In simple sense page is initialised and process completes.
PreLoad:
This event is called before the loading of the page is completed.
Load:
This Load means
that all the controls have been loaded completely . This implies that the control properties and the view state can be
accessed at this point/cycle.
This works like
initially , the Page Object calls the
OnLoad method on the Page object itself
and then OnLoad method of the
control is called . This means that the
Load event of Page occurs before Load event of the controls .
ControlEvents:
This event manages
the events for the buttons , textboxes etc
Like button click event , textbox : textchange event .
In the case of
postback , the Page.Isvalid property checks
if the page contains validator controls .
LoadComplete :
This means that the
page has been loaded in the memory. It also marks the beginning of the
rendering stage and occurs after the
event handling stage. This event is used for tasks such as loading all other
controls on the page.
PreRender:
If you need to make
any final changes /modification to the
contents of the controls or the page, then we use this event. In this event the PreRender event of the page is called first and later for the child control.
For eg : To set the DataSourceId Property and calling the DataBind method.
PreRenderComplete:
This event is raised after each control's PreRender property/phase is completed.
SaveStateComplete:
In this event, the
current state of the control is completely saved to the ViewState.This is raised after the control state and view
state have been saved for the page and for all controls.
RenderComplete:
The page object calls this
method on each control which is present on the page. This method writes
the control’s markup to send it to the browser.
Unload:
This event is typically used for
closing files and database
connections.
