How can we identify that the Page is Post Back?

Page object has an "IsPostBack" property, which can be checked to know that is the page posted back.

Page's IsPostBack property in asp.net.
you can also figure out by checking the value for the hidden control __EVENTTARGET and __EVENTARGUMENT where __EVENTTARGET contains the control id caused the postback and later one will hold the value

if (basename($_SERVER['HTTP_REFERER']) == $_SERVER['YOUR_SCRIPT_NAME']) { // DO SOMETHING }

Page.IsPostBack method

With the help of “IsPostBack” property In Asp.net we can check if a page is rendered for the first time or responding to a post back.

Eg:

            protectedvoid Page_Load(object sender, EventArgs e)

                {

                if (!IsPostBack)

                {

                    // Can write code here or call the method you want

                }

 

                if (IsPostBack)

                {

                     //Can write code here or call the method you want

                }

 

                }  

Page object has an "IsPostBack" property, which can be checked to know that is the page posted back to server or not, if "IsPostBack" property is "True" then page called postback and page loading through the "Post" Request (page loading second or higher time) else if "IsPostBack" property returns false then page is loading through "Get" Request (page loading first time).

by checking the control's property 'IsPostBack'

In Page_Load Event of your page you can test "IsPostBack" Property of your page instance.

in the Page_Load Event check this condition if(isPostBack == false) { // here your code }