What is an UpdatePanel?
Introduction. UpdatePanel controls are a central part of AJAX functionality in ASP.NET. They are used with the ScriptManager control to enable partial-page rendering. Partial-page rendering reduces the need for synchronous postbacks and complete page updates when only part of the page has to be updated.
What happens when a button placed in the UpdatePanel control is clicked?
The UpdatePanel control contains a Button control that refreshes the content inside the panel when you click it. By default, the ChildrenAsTriggers property is true. Therefore, the Button control acts as an asynchronous postback control.
Which of the following is the property of UpdatePanel control?
If the UpdateMode property is set to Always, the UpdatePanel control’s content is updated on every postback that originates from anywhere on the page. This includes asynchronous postbacks from controls inside other UpdatePanel controls and postbacks from controls that are not inside UpdatePanel controls.
How to update the top UpdatePanel in Firebug?
(If you inspect the DOM tree in FireBug, you will notice that the labels are dimmed to indicate that they are not producing visible content). Click the Update This Panel button, and notice the top UpdatePanel will be updated with the current server time. In FireBug, choose the Console tab so that you can examine the request.
How does the update panel work in ASP.NET?
The panel content changes every time that you click the button, but the whole page is not refreshed. By default, the ChildrenAsTriggers property of an UpdatePanel control is true. When this property is set to true, controls inside the panel participate in partial-page updates when any control in the panel causes a postback.
What happens when the parent UpdatePanel is triggered?
Note that when UpdatePanel controls are nested, when the UpdateMode is set to Conditional, if the child UpdatePanel is triggered, but the parent is not, then only the child UpdatePanel will refresh. However, if the parent UpdatePanel is refreshed, then the child UpdatePanel will also be refreshed.
Which is the trigger element in Ajax UpdatePanel?
One of which is the Triggers element, which specifies the controls on the page (or the user control, if you are using one) that will trigger a partial render of the UpdatePanel control in which the element resides.