ASP.NET Interview Questions Part-1

Qus1 : ASP .Net Page Life Cycle.

Ans1 :

1. OnInit (Init) Initializes each child control of the current

2. LoadControlState: Loads the ControlState of the control. To use this method the control must call the Page.RegisterRequiresControlState method in the OnInit method of the control.

3. LoadViewState: Loads the ViewState of the control.

4. LoadPostData: Is defined on interface IPostBackDataHandler. Controls that implement this interface use this method to retrieve the incoming form data and update the control s properties accordingly.

5. Load (OnLoad): Allows actions that are common to every request to be placed here. Note that the control is stable at this time; it has been initialized and its state has been reconstructed.

6. RaisePostDataChangedEvent: Is defined on the interface IPostBackData-Handler. Controls that implement this interface use this event to raise change events in response to the Postback data changing between the current Postback and the previous Postback. For example if a TextBox has a TextChanged event and AutoPostback is turned off clicking a button causes the Text-Changed event to execute in this stage before handling the click event of the button which is raised in the next stage.

7. RaisePostbackEvent: Handles the client-side event that caused the Postback
to occur

8. PreRender (OnPreRender): Allows last-minute changes to the control. This
event takes place after all regular Post-back events have taken place. This event takes place before saving ViewState so any changes made here are saved.

9. SaveControlState: Saves the current control state to ViewState. After this stage any changes to the control state are lost. To use this method the control must call the Page.RegisterRequiresControlState method in the OnInit method of the control.

10. SaveViewState: Saves the current data state of the control to ViewState. After this stage any changes to the control data are lost.

11. Render: Generates the client-side HTML Dynamic Hypertext Markup Language (DHTML) and script that are necessary to properly display this control at the browser. In this stage any changes to the control are not persisted into ViewState.

12. Dispose: Accepts cleanup code. Releases any unman-aged resources in this stage. Unmanaged resources are resources that are not handled by the .NET common language runtime such as file handles and database connections.

13. UnLoad: Set of subprograms that are executed towards each time of web page processing are called page life cycle events

14. Page Preinit: This will be executed before memory initialization for web page [before constructing web page.

15. Page init: This will be executed when memory is initialized for webpage

16. Page load: This will be executed when submitted data and controls are loaded. Database connectivity reading submitted data can be placed within pageload

17.PagePrerender: This will be executed before rendering html content from server side control

18. Page Unload: This will be executed once memory is released for webpage.

Qus3: What methods are fired during the page load?
Ans: Init() - when the page is instantiated.
Load() - when the page is loaded into server memory.
PreRender() - the brief moment before the page is displayed to the user as HTML.
Unload() - when page finishes loading.