ASPxGridView enables you to asynchronously go to the server and perform server-side processing using AJAX-based callback technology. To enable a callback mode, turn on the ASPxGridBase.EnableCallBacks option. Otherwise, round trips to the server are performed using standard postbacks (the whole page is refreshed).
Custom callbacks enable you to perform required server-side actions. After a custom callback has been performed, ASPxGridView is re-rendered.
To send a custom callback to the server, use the ASPxClientGridView.PerformCallback method. This method generates the server-side ASPxGridView.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.
Changing the settings of other controls contained on the page has no effect, because a custom callback only contains the information about ASPxGridView.
Don't export ASPxGridView content during callbacks, because ASP.NET does not support sending binary content during a callback.
The view state isn't updated during a callback.
How to Show Detail Information in a Separate ASPxGridView
This example demonstrates how to use two ASPxGridView instances to show the master-detail data. Detail data is displayed in an external ASPxGridView when a master ASPxGridView's focused row index is modified.
Partial Public Class Master_Detail_Two_Grids
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
adsProducts.SelectParameters("CategoryID").DefaultValue = gvMaster.GetRowValues(gvMaster.FocusedRowIndex, "CategoryID").ToString()
Protected Sub gvDetail_CustomCallback(ByVal sender As Object, ByVal e As DevExpress.Web.ASPxGridView.ASPxGridViewCustomCallbackEventArgs)
Dim categoryId As String = gvMaster.GetRowValues(gvMaster.FocusedRowIndex, "CategoryID").ToString()
adsProducts.SelectParameters("CategoryID").DefaultValue = categoryId
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, ASPxGridView enables you to perform custom data callbacks.