A TV set will support only one resolution, possibly something like 1366x768 in 16:9 widescreen.
This will have some issues with displaying a computer signal. It is feasible but more complicated.
Gaming consoles don't have DVI or VGA outputs to be directly compatible with a standard computer monitor
Your best bet would be to get a widescreen computer monitor that has components inputs (and, even better, HDMI) in addition to standard DVI and VGA connectors.