Vista - WPF Grid?

All:

I am writing a simple Jeopardy-like game for some kids... and I figured
a Grid would be a good way to lay out the game board. My (basic?)
question is, once I have a Grid object, is it possible to access the
Grid by Row and Column? For example, I'd like to say (in code), "Go to
'cell' 2,3 and paint the background blue. Go to 'cell' 1,2 and paint
the background green."

Is this possible? If not, do I simply have to slog through the
calculations "old school" and compute the client rectangle, the # of
columns, etc.


Thanks,
jpuopolo