How to config MacVim to support command/control key + arrow key to switch between windows?

here is the config file of my vimrc, but it doesn't work on my mac ,

"ctrl + left
imap <silent> <C-left> <esc><C-W><left>
vmap <silent> <C-left> <esc><C-W><left>
nmap <silent> <C-left> <C-W><left>
"ctrl + right
imap <silent> <C-right> <esc><C-W><right>
vmap <silent> <C-right> <esc><C-W><right>
nmap <silent> <C-right> <C-W><right>
"ctrl + up
imap <silent> <C-up> <esc><C-W><up>
vmap <silent> <C-up> <esc><C-W><up>
nmap <silent> <C-up> <C-W><up>
"ctrl + down
imap <silent> <C-down> <esc><C-W><down>
vmap <silent> <C-down> <esc><C-W><down>
nmap <silent> <C-down> <C-W><down>

so how to config it ? which character should I use instead of "C" ? thanks

It appears you want <D-down> for Cmd-Down (and -right/-up-/-left for the others). Seems to work in my testing.