Processing Custom Callbacks
- 2 minutes to read
ASPxVerticalGrid enables you to asynchronously go to the server and perform server-side processing using AJAX-based callback technology. Turn on the ASPxGridBase.EnableCallBacks option to enable the callback mode. Otherwise, round trips to the server are performed using standard postbacks (refreshing the whole page).
Custom Callbacks
Custom callbacks enable you to perform the required server-side actions. After a custom callback has been performed, ASPxVerticalGrid is re-rendered.
Use the ASPxClientVerticalGrid.PerformCallback method to send a custom callback to the server. This method generates the server-side ASPxVerticalGrid.CustomCallback event. The method’s args argument allows you to pass information from the client-side to the server. If specified, it is passed to the event handler as the Parameters property.
Handle the ASPxClientVerticalGrid.BeginCallback and ASPxClientVerticalGrid.EndCallback events if you need to perform actions on the client-side before and after callback processing.
Restrictions:
- Changing the settings of other controls contained on the page has no effect because a custom callback only contains the information about ASPxVerticalGrid.
- Do not export ASPxVerticalGrid content during callbacks, because ASP.NET does not support sending binary content during a callback.
- The view state does not update during a callback.
Custom Data Callbacks
When developing web applications, you often need to perform specific actions on the server and send the result back to the client for further processing. To make this task easy, the ASPxVerticalGrid enables you to perform custom data callbacks.
Use the client-side ASPxClientVerticalGrid.GetValuesOnCustomCallback method to initiate a custom data callback. This method generates the server-side ASPxVerticalGrid.CustomDataCallback event. The method’s args argument (if specified) is passed to the event handler as the Parameters property.
After the callback is processed in the ASPxVerticalGrid.CustomDataCallback event handler, the resulting information can be passed back to the client side’s function, specified by the onCallback parameter. The event’s ASPxGridCustomDataCallbackEventArgs.Result property specifies this information.
Note
Modifying ASPxVerticalGrid settings during a custom data callback has no effect because ASPxVerticalGrid is not re-rendered after a custom data callback.