Specifying Whether Controls Post to the Server
By default, information and selections that the user specifies in a Web Forms page are not posted immediately to the server. Instead, the values are posted only when the entire form is posted, usually in response to clicking a button. However, you might find it useful at times to send user changes to the server immediately.
To post control values to the server immediately
- Set the control's AutoPostBack property to true.
You can also respond to user actions by creating client scripts. For example, you can create a client script to respond to the Click event of a button or check box. For more information, see Client Script in Web Forms Pages.