ASP.NET Page Life Cycle Events

Pre Init:

• Check for "IsPostBack" property to determine whether this is the first time the page is being processed.
• Create or recreate dynamic controls.
• Set master page dynamically & theme property also.
• Read or set profile property values.
• This event can be handled by overloading the OnPreInit method or creating the Page-PreInit handler.

Init:

• In the Init event of the individual controls occurs first, later the Init event of the page takes place.
• This event is used to initialize control properties.
• This event can be handled by overloading the OnInit method or creating a Page-Init handler.

InitComplete:

• This event allows tracking of View State.
• Raised at the end of the page's initialization stage.
• View state tracking enables controls to persists any values that are programmatically added to the view state collection.
• Untill view state  tracking is turned on, any values added to view state are lost across postbacks.
• Controls typically turn on view state tracking immediately after they raise their Init event.
• Any changes made to the view state in this event are persisted even after the next postback.

PreLoad:

• This event process the postback data that is included with the request.

Load:

• In this event the page object calls the onload method on the page object itself, later the onload method of the controls is called.
• This load event of the individual controls occurs after the load event of the page.

Control Events:

• This event is used to handle specific control events such as button control's click event or a textbox control's TextChanged event.

LoadComplete:

• This event occurs after  the event handling stage.
• This event is used for tasks such as loading all other controls on the page.

PreRender:

• PreRender event of the pageis called first and later for the child controls.
• This event is used to make the final changes to the controls on the page like assigning the DataSourceID and calling the DataBind Method.
• Prerender event occurs just before the output is rendered.
• By handling this event, pages & controls can perform any updates before the output is rendered.

Prerender Complete:

• This event is raised after each control's Prerender property is completed.

SaveState Complete:

• This event is raised after the control state & view state have been saved for the page and for all controls.
• The HTML markup is generated.

Render Complete:

• The page object calls this method on each control which is present on the page.
• This method write's the control's markup to send it to the browser.

Unload:

• This event is raised for each control and then for the page object.
• Use this event in controls for final cleanup work, such as closing open database connections, closing open files, etc.