Gets or sets the identifier for the default button that is contained in the Panel control.
Assembly: System.Web (in System.Web.dll)
Use the property to indicate which button gets clicked when the Panel control has focus and the user presses the ENTER key. The can be set to the identifier for a Button control or any control that implements the IButtonControl interface except a LinkButton control.
Setting the property is not supported for the following scenarios:
Setting focus outside of the input controls in the panel and then pressing the ENTER key. The default post back action is not guaranteed to trigger.
Changing the programmatically during an asynchronous post back when the Panel control is not inside of an UpdatePanel control. Asynchronous post backs can be enabled on a page by adding one or more UpdatePanel controls to the page. UpdatePanel controls can be used to update selected regions of a page instead of updating the whole page with a postback. For more information, see UpdatePanel Control Overview and Partial-Page Rendering Overview.