---
title: "ICallBackDataHandler Interface"
canonical: https://www.graphicsmill.com/docs/gm5/T_Aurigma_GraphicsMill_AjaxControls_ICallBackDataHandler.htm
product: "Graphics Mill 5.5 for .NET"
---

This documentation is for the old version. [Go to the latest Graphics Mill docs](https://www.graphicsmill.com/docs/gm/)

# ICallBackDataHandler Interface
 
This interface is implemented by all the controls which can change their states during execution of the callback initiated by another control.
 
**Namespace:** [Aurigma.GraphicsMill.AjaxControls](https://www.graphicsmill.com/docs/gm5/N_Aurigma_GraphicsMill_AjaxControls.htm.md)
 **Assembly:** Aurigma.GraphicsMill.AjaxControls (in Aurigma.GraphicsMill.AjaxControls.dll)
 
## Syntax
  
```
Public Interface ICallBackDataHandler
```
 
```csharp
public interface ICallBackDataHandler
```
 
## Remarks
 This interface has one method which returns the string used to update the client-side object corresponded to the server-side control.
   
## See Also

### Reference

- [ICallBackDataHandler Members](https://www.graphicsmill.com/docs/gm5/AllMembers_T_Aurigma_GraphicsMill_AjaxControls_ICallBackDataHandler.htm.md)
- [Aurigma.GraphicsMill.AjaxControls Namespace](https://www.graphicsmill.com/docs/gm5/N_Aurigma_GraphicsMill_AjaxControls.htm.md)