How to implement Multiple UNDO and REDO for Editor

Hi,

I developed an Editor similar to Wordpad Application using Rich Text Box Control. I want to implement multiple Undo and Redo options for this. I believe there are some
API's related to this. Like what I know that there is one message for EditBox Controls called EM_UNDO. How to implement this.

Can u let me know any idea about this.

Regards

Prasad
contact : [email protected]