We are not sure what you mean by moving to 'the next cell'.
Do you want the user not to move to the next (insertion) row when the user press Enter if other cells on the right are still empty, but perhaps you want to move to the next insertion row if all the cells are filled? And if Enter is pressed when you're at the extreme right of the row, but if some cells that are still empty of the left, you go to the empty cells first instead of adding a new insertion row?
This is a complex question and a "code example" could take anything from a couple of lines to more than a hundred lines, depending of several factors.
Technical Support and software developer
Xceed Software Inc.
Knowledge Base : http://xceed.com/kb/
Update Center : http://xceed.com/updates/
Documentation Center : http://xceed.com/doc/
For everything else, there is Google