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.

What is the name of the Web page property that you can query to determine that a Web page is being requested without data being submitted?

IsPostBack.

What is isPostback property?

This property is used to check whether the page is being loaded and accessed for the first time or whether the page is loaded in response to the client postback.
Example:-
Consider two combo boxes In one lets have a list of countries In the other, the states. Upon selection of the first, the subsequent one should be populated in accordance. So this requires postback property in combo boxes to be true.

How do you indentify that the page is post back?

By checking the IsPostBack property. If IsPostBack is True, the page has been posted back.

How can we identify that the Page is Post Back?

Page object has an “IsPostBack” property

How will you identify whether the page is post backed or not?

Using “IsPostBack” property, you will identify whether the page is post backed or not.

Example

protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
//code that runs first time not execute when page is post back.
}
}

What is IsPostback property in asp.net and how does it work?

IsPostBack property indicates that whether this is the first time user has requested fort the page or it is reloaded based on any response on postback.

This property checks for __VIEWSTATE or __EVENTTARGET parameter in Request object. if these parameters are absent that means it is requested for the first time and if these parameters are present then this request is not first request.