CallbackError event handler is not invoked on a callback error

Hello,

In order to override callback error messages or handle callback exceptions in the required manner, set the ASPxWebControl.CallbackError event handler.
In this handler, determine the type of the exception and override the default exception handling process. For example:

1. When you are trying to upload a file and there is an exception on the server side, the exception message is not informative enough or gives a user too much technical info.

C#
public static void FileUploadComplete(object sender, DevExpress.Web.FileUploadCompleteEventArgs e) {  
    throw new Exception("CallbackException. Some error message you want to override!");  
}  

2. When you set the ASPxWebControl.CallbackError event handler, you are able to override the default callback handling behavior. You can, for example, change the callback error message using ASPxWebControl.SetCallbackErrorMessage.

C#
protected void Application_Start() {  
    ...  
    DevExpress.Web.ASPxWebControl.CallbackError += Application_Error;  
}  

protected void Application_Error(object sender, EventArgs e) {  
    Exception exception = System.Web.HttpContext.Current.Server.GetLastError();  
    if(exception.Message.StartsWith("CallbackException."))  
        DevExpress.Web.ASPxWebControl.SetCallbackErrorMessage("Upload failed. Please try again later.");  
}  

I have created a sample project to illustrate this approach.

Best regards,
Pavlo