I am looking to the developers who have been around before. NET and really don't take these kinds of things for granted. Books and hyperlinks are reasonable answers or additions to your answer. So far I've seen the right answer alluded to repeatedly, and almost everyone has come shy of what I consider subjectively to be the mark. Well, those are the two a programmer uses most frequently. The others all have some purpose, if they're implemented on the server. It's sort of a hack that we all agree is an actual use, and not a hack.
Whether that makes it a hack or an actual implementation detail I leave up to you. So when you send the body of the POST skipping the others for now, you can figure it out from here with the form elements, you're sending back certain elements.
How those elements are defined is up to you and to the environment you're working in. Now everyone says, "oh, a postback is a subsequent request to a page. I say this because the difference between a GET request and a POST request is if data is included in the body and the verb used, but the client usually knows how to deal with that. You could postback to the page on the first time the page is visited, and in fact ASP.
NET has tools for doing that in the library. You could certainly have a desktop client POST data to a server think Twitter without showing any webpage at all from the server ok, so twitter is probably not the best concept to use for an example here, but I want to illustrate that you can use a client that doesn't show the webpage, so no request is necessary. But I hope you can see that it doesn't have to be in that order.
Does the same thing, but violates that concept of only using GET for requests. It's how come you can send someone a link to a google search, for instance. See ASP. A PostBack is any request for a page that is not the first request. This results in complex code IsPostback, This enables you page to go through the asp engine on the server and any dynamic content to be updated.
Net uses a new concept well, new compared to asp What does this mean? In a nutshell, if you type something into a textbox or select a dropdown from a dropdownlist, it will remember the values when you click on a button. Old asp would force you to write code to remember these values.
This is useful when if a user encounters an error. Instead of the programmer having to deal with remembering to re-populate each web control, the asp. It's also useful because now the code behind can access the values of these controls on your asp. As for posting to the same page, yes, a "submit" button will post to an event handler on the code behind of the page.
It's up to the event handler in the code behind to redirect to a different page if needs be or serve up an error message to your page or whatever else you might need to do. Postbacks can be either full refresh the entire page or partial in a case where AJAX is employed.
A partial page postback will re-render only a part of the page like a single drop-down list, a table, etc. In the old HTML, the only way to make something updated on the webpage is to resend a new webpage to the client browser. That's what ASP used to do, you have to do this thing call a "PostBack" to send an updated page to the client. In ASP. NET, you don't have to resend the entire webpage.
NET controls such that you don't have to resend the entire webpage. If you visit some old website, you would notice that once you click something, the entire page has to be refresh, this is the old ASP. In most of the modern website, you will notice your browser doesn't have to refresh the entire page, it only updates the part of the content that needs to be updated.
For example, in Stackoverflow, you see the page update only the content, not the entire webpage. PostBack is done if certain credentials of the page are to be checked against some sources such as verification of username and password using database.
This is something that a client machine is not able to accomplish and thus these details have to be 'posted back' to the server. A post back is round trip from the client Browser to the server and then back to the client. This enables you page to go through the asp engine on the server and any dynamic content to be updated.
Post back is implemented with the use javascript in the client side. The HTML page generated for each. This makes the page to be posted on to itself. If we check the entry on the HTML file, it will look something like this. Also, all the validation code that is written Required Field Validation, Regular Expression validation etc. With this new ASP.
Net model, even if the user wants to post the data to a different. A simple declaration as in the following code snippet will be enough to create such a web form. AutopostBack is a property which you assign to web controls if you want to post back the page when any event occurs at them.
NET also adds two additional hidden input fields that are used to pass information back to the server. This information consists of ID of the Control that raised the event and any additional information if needed.
These fields will empty initially as shown below,. Sign in Email. Forgot your password? Search within: Articles Quick Answers Messages. Tagged as. PostBack is the name given to the process of submitting all the information that the user is currently working on and send it all back to the server. Postback is actually sending all the information from client to web server, then web server process all those contents and returns back to client.
A postback originates from the client side browser. When the web page and its contents are sent to the web server for processing some information and then, the web server posts the same page back to the client browser. Normally one of the controls on the page will be manipulated by the user e.
Then the state of this control and all other controls on the page is Posted Back to the web server. NET also adds two additional hidden input fields that are used to exchange information back to the server.
This information consists of ID of the Control that raised the event and any additional information if needed. These fields will empty initially like the following:. You can also pass an event argument along with the target in case you need to pass something to your code behind:. This would be captured in the code behind as Request. Home C VB. What is a postback Postback All the web applications are running on Web Servers.
Example: if! Next : What is IsPostBack. Net Interview Questions Part-1 Asp. Net tracing Passing values between Asp.
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