Page life cycle of ASP.net

Methods	Description
Page_Init	Page Initialization
LoadViewState	View State Loading
LoadPostData	Postback Data Processing
Page_Load	Page Loading
RaisePostDataChangedEvent	PostBack Change Notification
RaisePostBackEvent	PostBack Event Handling
Page_PreRender	Page Pre Rendering Phase
SaveViewState	View State Saving
Page_Render	Page Rendering
Page_Unload	Page Unloading

The first processed method is Page_Init(). Once the control tree has been created, the controls declared in the .aspx file are initialized. The controls can modify some of the settings set in this method to be used later in the page life cycle. Obviously no other information is available to be modified at this time.

The next processed method is LoadViewState(). The Viewstate contains stored information that is set by the page and controls of the page. This is carried to and from every aspx page request per visitor.

The next processed method is LoadPostData(). These are values associated with the HTML form elements the visitor has typed, changed or selected. Now the control has access to this information which can update their stored information pulled from the Viewstate.

The next processed method is Page_Load(). This method should look familiar and is usually the most common used method on the server side application code for an .aspx file. All code inside of this method is executed once at the beginning of the page.

The next processed method is RaisePostDataChangedEvent(). When a visitor completes a form and presses the submit button, an event is triggered. This change in state signals the page to do something.

The next processed method is RaisePostBackEvent(). This method allows the page to know what event has been triggered and which method to call. If the visitor clicks Button1, then Button1_Click is usually called to perform its function.

The next processed method is Page_PreRender(). This method is the last chance for the Viewstate to be changed based on the PostBackEvent before the page is rendered.

The next processed method is SaveViewState(). This method saves the updated Viewstate to be processed on the next page. The final Viewstate is encoded to the _viewstate hidden field on the page during the page render.

The next processed method is Page_Render(). This method renders all of the application code to be outputted on the page. This action is done with the HtmlWriter object. Each control uses the render method and caches the HTML prior to outputting.

The last processed method is Page_Unload(). During this method, data can be released to free up resources on the server for other processes. Once this method is completed, the HTML is sent to the browser for client side processing.