How can I programatically control multi-display setup?

I use a laptop +a widescreen monitor, as dual screen setup. Half the time when I reconnect the laptop back a开发者_Go百科fter working on it standalone , the dual-screen settings gets automatically switched to "single screen" and I have to go and switch it back.

How can I do that programatically?

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there is a keyboard shortcut
[Windows key] + [P]