Tab

ASPxPageControl.EnableCallBacks Property

Gets or sets a value that specifies whether callback or postback technology is used to manage round trips to the server.

Namespace: DevExpress.Web

Assembly: DevExpress.Web.v21.1.dll

Declaration

[DefaultValue(false)]
public bool EnableCallBacks { get; set; }

Property Value

Type Default Description
Boolean

false

true if round trips to the server are performed using callbacks; false if postbacks are used.

Remarks

The ASPxPageControl’s behavior is based upon the combination of ASPxTabControlBase.AutoPostBack and EnableCallBacks property settings, which can be as follows:

  • If the ASPxTabControlBase.AutoPostBack and EnableCallBacks properties are set to false (the default behavior), the ASPxPageControl works in the so called “client mode”. In this mode, the contents of all its pages (active and inactive) are sent to the client during the first response, and active page alteration is performed on the client side without generating any round-trip to the server. In this situation, you can utilize the control’s client-side object model (client events and methods) to respond to client-side manipulations.
  • If the ASPxTabControlBase.AutoPostBack property is set to true, the EnableCallBacks property is not in effect, and the ASPxPageControl works in “server mode”. In this mode, only the active page’s content is sent to the client side on the first response. Then, any change to the active page generates a postback of the entire web page, which is processed on the server side (the server ASPxTabControlBase.ActiveTabChanged event is always generated in this case). Note that in this mode, you can send a callback to the server and reload an active page using the ASPxClientPageControl.PerformCallback method.
  • If the ASPxTabControlBase.AutoPostBack property is set to false, and the EnableCallBacks property is set to true, the ASPxPageControl functions in the following manner. During the first response, only the content of the active page is sent to the client side. When the active page changes, the content of the new active page is loaded from the server only once - it is performed dynamically via a callback without refreshing the entire web page. When all pages are loaded to the client in this manner, the ASPxPageControl switches to the “client mode”, and further work is performed without generating round-trips to the server. So, the server-side ASPxTabControlBase.ActiveTabChanged event is called only once for each page in this mode.
See Also