How to call method dispatch from class CL_GUI_ALV_GRID

Hello Everyone,

I'm developing a copy from a standard transaction S_ALR_87013542.

I want to put a button in an ALV there is in this transaction, so I'd like to know how to call the method dispatch of the class CL_GUI_ALV_GRID without calling the standard transaction.

Any help would be very appreciated.

Thanks in Advance.