What is page execution life cycle? OR Life – Cycle Events?

Following are the sequence of events that raised whenever you request a page:
     1)    PreInit
     2)    Init
     3)    InitComplete
    4)    PreLoad
   5)    Load
  6)    LoadComplete
  7)    PreRender
  8)    PreRenderComplete
  9)    SaveStateComplete
 10)    Unload
Note: - View State is not loaded until after the InitComplete event. Data posted to the server from a form control, such as a TextBox control is also not available until after this event.
 1)    PreInit: - Use this event for the following:
        •    Check the IsPostBack property to determine whether this is the first time the page is being processed.
        •    Create or re-create dynamic controls.
        •    Set a master page dynamically.
        •    Set the Theme property dynamically.
        •    Read or set profile property values.
Note: - If the request is a postback, the values of the controls have not yet been restored form view state. If you set a control property at this stage, its value might be overwritten in the next event.
  2)    Init: - Raised after all controls have been initialized and any skin settings have been applied. Use this event to read or initialize control properties.
  3)    InitComplete: - Raised by the Page object. Use this event for processing tasks that require all initialization be complete.
  4)    PreLoad: - Use this event if you need to perform processing on your page or control before the Load event. Before the Page instance raises this event, it loads view state for itself and all controls, and then processes any postback data included with the Request instance.
  5)    Load: - The Page calls the OnLoad event methods on the Page, then recursively does the same for each child control, which does the same for each of its child controls until the page and all the controls are loaded. Use the OnLoad event method to set properties in controls and establish database connections.
  6)    LoadComplete: - Use this event for tasks that require that all other controls on the page be loaded.
  7)    PreRender: - Before this event occurs:
    •    The Page object calls EnsureChildControls for each control and for the page.
    •    Each data bound control whose DataSourceID property is set calls its DataBind method.
The PreRender event occurs for each control on the page. Use the event to make final changes to the contents of the page or its controls.
  8)    PreRenderComplete: - Occurs before the page content is rendered.
The PreRenderComplete event is raised when the pre-render stage of the page life cycle is complete. At this stage of the page life cycle, all controls are created, any pagination required is completed, and the page is ready to render to the output.
This is the last event raised before the page’s view state is saved.
   9)    SaveStateComplete: - Before this event occurs, ViewState has been saved for the page and for all controls. Any changes to the page or controls at this point will be ignored.
Use this event perform tasks that require view state to be saved, but that do not make any changes to controls.
   10)    Unload: - This event occurs for each control and then for the page. In controls, use this event to do final cleanup for specific controls, such as closing control-specific database connections.
For the page itself, use this event to do final cleanup work, such as closing open files and database connections, or finishing up logging or other request-specific tasks.