I had a case where I wanted to show an ASPxLoadingPanel when the user changed the the selection. On a command button this is easy you just add a OnClientClick="ShowLoadingPanel()".
But since a Drop Down you need to show the loading panel on the Change Event DevExpress does not handle that unless you are doing a call back. In this case I had an ASPxComboBox on a page with an Update Panel and a Grid.
To get around this I added the following JavaScript in the C# code behind:
BtnRefresh.Attributes.Add("onclick", "javascript:ShowLoadingPanel();");
Which calls...and shows the spinner.
function ShowLoadingPanel() {
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_initializeRequest(prm_InitializeRequest);
prm.add_endRequest(prm_EndRequest);
}
function prm_InitializeRequest(sender, args) {
LoadPnlAcctGridDev.Show();
}
function prm_EndRequest(sender, args) {
LoadPnlAcctGridDev.Hide();
}
Once the Grid is reloaded the spinner is gone...