You do not call the event. You subscribe to it, add your event handler, and then when the event is raised, your event handler code is hit. Normally, you never really call your code.
Here is a sample that subscribes to the grid.Model.PasteCellText event. In the handler, the code checks if the values in column 2 are ints. If not, it does not allow the paste.
GridDataBoundGridPasteCellText_6595.zip