Why we use (!IsPostBack) in c#?

Question

What is the use of (!IsPostBack)

if (!IsPostBack)    
 {
 // Validate initially to force asterisks
 // to appear before the first roundtrip. 
        Validate();
 }

Answer 1

check below link . It will help you .

http://www.dotnetspider.com/resources/189-AutoPostBack-What-it-is-and-How-it-works.aspx

http://www.codeproject.com/Articles/811684/Understanding-The-Complete-Story-of-Postback-in-AS

Answer 2

IsPostBack is read only property.

it return true if the page is being loaded in response to a client postback; else set to false. for example if i have page and it has button control.
when page is first lime load this property is set to false.
when use click on button then client post bask is occur so it set to true.

Answer 3

Hi,

 

Using of the IsPostback Property we can check that page is Postback or not if page postback property is true then page is being post back if property is false then page is not postback

 

Reference :

 

https://www.youtube.com/watch?v=yZJQ4Z6kEzs

Answer 4

First of all, "IsPostBack" is an property in ASP.Net Page andit returns truewhen the page postedback by server otherwise it will return true.

Say for example, you have a button in an aspx page and when yourequest the page in the url, the "ispostback" propertyset as "false"when you click on the buttonthe page will submit ( postedback)to the web server (IIS) and the page is processed by the IIS and sent it to browser. At this time it will set the "ispostback" as true.

https://msdn.microsoft.com/en-us/library/system.web.ui.page.ispostback(v=vs.110).aspx

Answer 5

IsPostBack property tells that the page is rendered first time or it is posted back by some server control. If it returns true, it means it is posted back by some control like button click.