What technique is used to figure out that the page request is a postback?

The IsPostBack property of the page object may be used to check whether the page request is a postback or not. IsPostBack property is of the type Boolean.

Which event of the ASP.NET page life cycle completely loads all the controls on the web page?

The Page_load event of the ASP.NET page life cycle assures that all controls are completely loaded. Even though the controls are also accessible in Page_Init event but here, the viewstate is incomplete.

How is ViewState information persisted across postbacks in an ASP.NET webpage?

Using HTML Hidden Fields, ASP.NET creates a hidden field with an ID=”__VIEWSTATE” and the value of the page’s viewstate is encoded (hashed) for security.

What is the ValidationSummary control in ASP.NET used for?

The ValidationSummary control in ASP.NET displays summary of all the current validation errors.

What is AutoPostBack feature in ASP.NET?

In case it is required for a server side control to postback when any of its event is triggered, then the AutoPostBack property of this control is set to true.

What is the difference between Web.config and Machine.Config in .NET?

Web.config file is used to make the settings to a web application, whereas Machine.config file is used to make settings to all ASP.NET applications on a server(the server machine).

What is the difference between a session object and an application object?

A session object can persist information between HTTP requests for a particular user, whereas an application object can be used globally for all the users.