How can autohotkey detect which virtual desktop you're on?

Question

Hi I'm new to autohotkey (and programming in general) and I wanted to write a script that lets me conveniently switch to a specific desktop. For example, in my script Capslock+3 switches to desktop 3.

As you can see or if you try it out, it's not very robust. The script only knows a desktop number separate from the real one. For example, if you run the script while on desktop 4, the script still starts with the desktop set to 1 and you have to press Caps+4 then Caps+1 to set it in the right direction. And if there is a flashing window in another desktop and you click it, it switches to that desktop while the script still thinks you're in the previous one.

I've searched for ways autohotkey can detect which desktop you're on, but could not find any.

Can anyone give any tips on how to improve it? Thanks! :D

SetCapsLockState, AlwaysOff
desktop = 1

Switch(d)
{
    global

    ;Determine how far away the desired desktop is from current one
    press := (d-desktop)

    desktop = %d%

    ;Determine which direction to switch desktops and stop script if already on current desktop
    If press < 0
        direction = Left
    else if press > 0
        direction = Right
    else
        return

    press := Abs(press)

    Loop, %press%
    {
        SendInput, ^#{%direction%}
        Sleep, 75
    }

    return
}

CapsLock & 1::
    Switch(1)
return

CapsLock & 2::
    Switch(2)
return

CapsLock & 3::
    Switch(3)
return

CapsLock & 4::
    Switch(4)
return

;In case user switches desktop with traditional shortcuts

^#Left::
    SendInput ^#{Left}
    If desktop > 1
        desktop--
return

^#Right::
    SendInput ^#{Right}
    If desktop < 4
        desktop++
return

Answer 1

source

RegRead, cur, HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\SessionInfo\1\VirtualDesktops, CurrentVirtualDesktop
RegRead, all, HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\VirtualDesktops, VirtualDesktopIDs
ix := floor(InStr(all,cur) / strlen(cur))
msgbox current desktop index: %ix%

If SessionInfo keeps changing (on a multiuser environment etc) then add a couple of Windows API calls:

SessionId := getSessionId()
RegRead, CurrentDesktopId, HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\SessionInfo\%SessionId%\VirtualDesktops, CurrentVirtualDesktop
msgbox % CurrentDesktopId 

getSessionId(){
    ProcessId := DllCall("GetCurrentProcessId", "UInt")
    if ErrorLevel return 1
    DllCall("ProcessIdToSessionId", "UInt", ProcessId, "UInt*", SessionId)
    if ErrorLevel return 1
    return SessionId
}

Answer 2

To get desktop name a bit of string re-arrangement is needed. Here's what I've got to ToolTip and display the desktop switch when performed by the standard windows hotkey of WinKey+Left/Right

ConvertIdToDesktopKey(id)
{
    arr := StrSplit(id)
    str := "{" . arr[7] . arr[8] . arr[5] . arr[6] . arr[3] . arr[4] . arr[1] . arr[2] . "-" .      arr[11] . arr[12] . arr[9] . arr[10] . "-" .        arr[15] . arr[16] . arr[13]  . arr[14] . "-" .      arr[17] . arr[18] . arr[19] . arr[20] . "-" . SubStr(id, -11) . "}"

    return str
}

GetSessionId(){
    ProcessId := DllCall("GetCurrentProcessId", "UInt")
    if ErrorLevel return 1
    DllCall("ProcessIdToSessionId", "UInt", ProcessId, "UInt*", SessionId)
    if ErrorLevel return 1
    return SessionId
}

RemoveToolTip:
ToolTip
Return

ToolTipCurrentDesktop:
    SessionId := GetSessionId()
    RegRead, cur, HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\SessionInfo\%SessionId%\VirtualDesktops, CurrentVirtualDesktop
    key := ConvertIdToDesktopKey(cur)
    RegRead, name, HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\VirtualDesktops\Desktops\%key%, Name
    ToolTip, - Desktop -`n%name%
    SetTimer, RemoveToolTip, -1800
Return

; Forward the standard windows shortcut for desktop switch, and set a timer for flashing the destination desktop name
#^Left::
    Send #^{LEFT}
    SetTimer, ToolTipCurrentDesktop, -800
Return

#^Right::
    Send #^{RIGHT}
    SetTimer, ToolTipCurrentDesktop, -800
Return