Skip to main content

Page life cycle of ASP.net page



The stsges of Page life cycle are as follows :
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

Page_Init :

The Page_Init event is the first event to be triggered in the page life cycle. In this the control tree has been created, the controls declared in the .aspx file are initialized. The viewstate is not available at this stage. We can create or re-create the controls that need to be created or re-created dynamically.

LoadViewState :

The Viewstate contains stored information that is set by the page and controls of the page. But the load view state event only occurs when the page has been posted back. Due to viewstate control's and page itself store information that is persistent among web requests. It contains the state of the controls the last time the page was processed on the server.

LoadPostData :

After viewstate is loaded the control are updated with posted values or values that are entered or changed by user.

Page_Load :

After Loadpostdata the page_load event is fired. In this event code written inside page load is executed once at the beginning of the page.

RaisePostDataChangedEvent :

In this event when user clicks submit button or any other button then it changes state of the page and the event related to that button is raised.

RaisePostBackEvent :

This methods knows which event has occurred and which related method you need to call like btnsubmit is clicked then it will call method related to it like “btnsubmit_click” to perform its functionality.

Page_PreRender :

At this stage page is prepared for Rendering and if user wants to chage anything he can change it here only as in this event viewstate is not saved and output is not rendered.

SaveViewState :

In this event values of viewstate is saved to control own viewstate collection. The resultant viewstate is serialized, hashed, base24 encoded and associated with the _viewstate hidden field.

Page_Render :

This method takes the HtmlWriter object and uses it to accumulate all HTML text to be generated for the control. For each control the page calls the render method and caches the HTML output.

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.

Comments

Popular posts from this blog

Dynamic Generation of Word Document Report in ASP.NET with HTML

Overview Ever needed to generate Word documents from your ASP.NET applications? There are a couple of components which will help to generate Word documents, but using these components may have some overhead such as Component Registration, setting permissions, licenses, etc., Sometimes, it may even become difficult to understand their features and use them. Generating word document in ASP.NET with HTML is incredibly easy. The following sample demonstrates how to place Heading and Table dynamically in the word document in ASP.NET web applications using HTML. Requirements Microsoft Visual Web Developer 2005 Express Edition Create the Web Application project Add the new Web Site Application project (with name as Generate Word Document) and place the button (with name as btnGenerateDocument) in the Default.aspx web form as shown below. Double click the highlighted code behind file from the Solution Explorer and add the following namespaces. Listing 1 using  System...

GRIDVIEW GROUPING

When displaying data, we sometimes would like to group data for better user experience or when displaying long list of hierarchal data, we would want to display them in a tree view kind of structure. There is more than way of doing this, but I am going to explain achieving this functionality using  AJAX Collapsible Panel Extender Control . Overview: I am going to use  Adventure Works  as datasource. Every product in  Production.Product  table belongs to a product sub category. We fetch handful of products and the sub categories they belong to from the database. Our objective is to list all the available sub categories and allow user to  expand/collapse  to look/hide the list of products belonging to each subcategory. Database Connection Added following entry under  connectionStrings  element in  web.config . < add   name = "Sql"   connectionString="Data Source=(local); Initial  Catalog = AdventureWorks ...

GRIDVIEW ZOOM IMAGE

When you have images in your  GridView , you would most likely show them as thumbnails so as to not distort the whole layout. However user would want to look at the full image by clicking on the image or just hovering his mouse over it. In today’s applications, this is a basic requirement and there are just so many third party controls or plugins which would support this functionality. I am going do this conventional way using  javascript  way in this article.  On top of it, I am also going to explain how to get images from database using  HttpHandlers . Example: I am using  Adventure Works  as datasource. We fetch handful of products and bind them to the grid. When page is initially loaded, we retrieve products from Production . Product  table and bind them to the grid. We display some product attributes such as Product ID, Product Number, Product Name, List Price and product’s thumbnail. When user hover his mouse on the page, we fetch the f...