# Server-Side Events Overview

The [ASP NET AJAX Calendar](https://www.telerik.com/products/aspnet-ajax/calendar.aspx) control raises server-side events, which you can use to customize the parts of the control as they are created, or to respond in the code-behind when the user makes a change.

**RadCalendar** exposes the following server-side events:

* [DayRender](https://www.telerik.com/products/aspnet-ajax/documentation/controls/calendar/server-side-programming/events/dayrender) occurs immediately before the calendar renders the cell for a single day in the day matrix.

* [HeaderCellRender](https://www.telerik.com/products/aspnet-ajax/documentation/controls/calendar/server-side-programming/events/headercellrender) occurs immediately before the calendar renders a cell in the column or row headers (or the view selector).

* [SelectionChanged](https://www.telerik.com/products/aspnet-ajax/documentation/controls/calendar/server-side-programming/events/selectionchanged) occurs when the user changes the current selection in the calendar. This event does not fire unless the **AutoPostBack** property is **True**.

* [DefaultViewChanged](https://www.telerik.com/products/aspnet-ajax/documentation/controls/calendar/server-side-programming/events/defaultviewchanged) occurs when the user changes the current view using the navigation controls in the title bar. This event does not fire unless the **AutoPostBack** property is **True**.

## Postbacks

By default, the **RadCalendar** does not cause postbacks when the user selects or deselects a date. This means that the server-side events are not raised. To enable postback to be triggered you should set the **AutoPostBack** property to **true**.