aspnetmvc-js-mvcxclientfilemanager-805780f0.md
Occurs when a callback for server-side processing is initiated.
BeginCallback: ASPxClientEvent<MVCxClientBeginCallbackEventHandler<MVCxClientFileManager>>
The BeginCallback event's data class is MVCxClientBeginCallbackEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| command | Gets a command name that identifies which client action initiated a callback. Inherited from ASPxClientBeginCallbackEventArgs. |
| customArgs | Gets an object containing specific information (if any, as name/value pairs) that should be passed as a request parameter from the client to the server side for further processing. |
The BeginCallback and ASPxClientFileManager.EndCallback events can be used to perform specific client-side actions (for example, to display and hide an explanatory text or picture) while a callback is being processed on the server side.
By handling the BeginCallback event, you can pass any required information from the client to the server via the MVCxClientBeginCallbackEventArgs.customArgs property.
See Also