Change Win-10 display settings on command line or via C#

Question

Context: Windows 10 Desktop PC "losing track" of screens, and they go/stay black

I want to mimic the effect of "changing the Windows Display config" (see end for the specific UI navigation) on a command line, so that I can set it up such that I can easily run the command/script with Keyboard only, without access to the monitors.

All I need is a script or exe that can do this, and then either I can use my keyboard's has programmable F-Keys, or I could do:

• Win-Key
• type "cmd"
• Enter
• type "reset_screens.sh/.cmd/.ps1/.exe/.whatever"
• Enter

So, how can I reproduce the effect of that UI interaction without the UI?

UI Sequence:

• Minimise everything down to desktop
• Context Menu for desktop background
• "Display Settings"
• Scroll down to "Multiple Displays".
• In the drop down change from "Extend these displays" to "Duplicate these display".
• What happens after that is irrelevant, as long as it then gets reversed

• Brondahl: These seem like promising links, but I haven't yet identified anything specificaly in them that would solve it :( (And I know that link-only answers aren't considered appropriate :D) codeproject.com/Articles/36664/… stackoverflow.com/questions/233411/…

Answer 1

There is a command that can do it called: DISPLAYSWITCH.exe Note this is the program that opens when you press Windows+P

I don't know how it works internally, but you can call it from C#.

The WIN32 command for updating these display settings seems to be: SetDisplayConfig

Syntax DISPLAYSWITCH /Option

Options

 /internal Switch to use the primary display only.
 1 All other connected displays will be disabled. 
 /clone The primary display will be mirrored on a second screen.
 2 
 /extend Expand the Desktop to a secondary display.
 3 This allows one desktop to span multiple displays. (Default).
 /external Switch to the external display only (second screen).
 4 The current main display will be disabled.

• Brondahl: Ooh! An exciting new development ... I'll take a look at this at some point in the (hopefully not too distant future) and accept if it works for me.
• Brondahl: Feel free to intermittently ping me if I haven't come back to accept / refute this after a few weeks :)