c# - Display Count (Inc. Disabled Displays) -

hello new stackoverflow.com. not sure how question asked here, doing best. done, quite research on subject, couldn't find single thing resolve detection.

example case: trying identify count of active , disabled displays in windows 7-10 systems.

code gpu[availability]:

        private int moncount;     [dllimport("user32.dll")]     private static extern bool enumdisplaydevices(         string lpdevice, int idevnum,         ref display_device lpdisplaydevice, int dwflags);      [structlayout(layoutkind.sequential)]     public struct display_device     {         public int cb;         [marshalas(unmanagedtype.byvaltstr, sizeconst = 32)]         public string devicename;         [marshalas(unmanagedtype.byvaltstr, sizeconst = 128)]         public string devicestring;         public int stateflags;         [marshalas(unmanagedtype.byvaltstr, sizeconst = 128)]         public string deviceid;         [marshalas(unmanagedtype.byvaltstr, sizeconst = 128)]         public string devicekey;          public display_device(int flags)         {             cb = 0;             stateflags = flags;             devicename = new string((char)32, 32);             devicestring = new string((char)32, 128);             deviceid = new string((char)32, 128);             devicekey = new string((char)32, 128);             cb = marshal.sizeof(this);         }     }     public void monitorcheck()     {         display_device lpdisplaydevice = new display_device(0);     // out         display_device monitor_name = new display_device(0);        // out          int devnum = 0;         while (enumdisplaydevices(null, devnum, ref lpdisplaydevice, 0))         {              listbox1.items.add("\ndevnum =" + devnum);             listbox1.items.add("cb =" + lpdisplaydevice.cb);             listbox1.items.add("deviceid =" + lpdisplaydevice.deviceid);             listbox1.items.add("devicekey =" + lpdisplaydevice.devicekey);             listbox1.items.add("devicename =" + lpdisplaydevice.devicename.trim());             listbox1.items.add("devicestring =" + lpdisplaydevice.devicestring.trim());             // show monitor name:             enumdisplaydevices(lpdisplaydevice.devicename, 0, ref monitor_name, 0);             listbox1.items.add("monitor name =" + monitor_name.devicestring.trim());             ++devnum;         }     } 

source: c# how windows monitor name

return: attachable monitors graphic adapter information. count how many monitors can attached in display adapter.

code active displays:

screen.allscreens.count(); 

return: active monitor count.

problem:

if gpu adapter has 3 outputs: * above gpu[availability] code returns: 3 (no matter how many displays attached it.)

if 2 monitors attached (example: laptop monitor + external hdmi monitor), display setup set to: laptop monitor (external hdmi monitor not active) -> active displays code returns: 1

question:

how return 2 there non-active display , active display attached (laptop monitor + non-active external monitor)?

solutions:

there's few ideas how resolve this:

1. activate displays extending them , redo: screen.allscreens.count();

idea: compare output of gpu[availability] output , count gives value monitor_name.devicestring.trim() (however, i've tested @ desktop having nvidia adapter: outcome null, in laptop intel hd adapter: output "generic pnp-monitor", so, no solution).

stupid me... never though use 3 methods solve problem. (seems damn hard code work in code tags here @ forums.

• maximum attachable displays
• currently attached displays
• currently active displays

solution:

hmm, can't seem able attach code stackoverflow reply, so:

pastebin: monitors counting