VirtualDesktopAccessor.dll

DLL for accessing Windows 10 (tested with 1809 build 17663) Virtual Desktop features from e.g. AutoHotkey. MIT Licensed, see LICENSE.txt (c) Jari Pennanen, 2015-2018

Download the VirtualDesktopAccessor.dll from directory x64\Release\VirtualDesktopAccessor.dll in the repository. This DLL works only on 64 bit Windows 10.

You probably first need the VS 2017 runtimes vc_redist.x64.exe and/or vc_redist.x86.exe, if they are not installed already. I've built the DLL using VS 2017, and Microsoft is not providing those runtimes (who knows why) with Windows 10 yet.

Change log

• 16.05.2021:

  Expose CreateVirtualDesktop and RemoveVirtualDesktop functions.

• 02.06.2019:

  Exported the Alt+Tab functions prefixed with View, this should allow user of the DLL to create native feeling ALT+Tab switcher, since these functions uses the same IApplicationView functions as real Alt+Tab switcher itself.

  The function to get Alt+Tab windows is basically ViewGetByLastActivationOrder.

AutoHotkey script as example:

DetectHiddenWindows, On
hwnd:=WinExist("ahk_pid " . DllCall("GetCurrentProcessId","Uint"))
hwnd+=0x1000<<32

hVirtualDesktopAccessor := DllCall("LoadLibrary", Str, "C:\Source\CandCPP\VirtualDesktopAccessor\x64\Release\VirtualDesktopAccessor.dll", "Ptr")
GoToDesktopNumberProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "GoToDesktopNumber", "Ptr")
GetCurrentDesktopNumberProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "GetCurrentDesktopNumber", "Ptr")
IsWindowOnCurrentVirtualDesktopProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "IsWindowOnCurrentVirtualDesktop", "Ptr")
MoveWindowToDesktopNumberProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "MoveWindowToDesktopNumber", "Ptr")
RegisterPostMessageHookProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "RegisterPostMessageHook", "Ptr")
UnregisterPostMessageHookProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "UnregisterPostMessageHook", "Ptr")
IsPinnedWindowProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "IsPinnedWindow", "Ptr")
RestartVirtualDesktopAccessorProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "RestartVirtualDesktopAccessor", "Ptr")
; GetWindowDesktopNumberProc := DllCall("GetProcAddress", Ptr, hVirtualDesktopAccessor, AStr, "GetWindowDesktopNumber", "Ptr")
activeWindowByDesktop := {}

; Restart the virtual desktop accessor when Explorer.exe crashes, or restarts (e.g. when coming from fullscreen game)
explorerRestartMsg := DllCall("user32\RegisterWindowMessage", "Str", "TaskbarCreated")
OnMessage(explorerRestartMsg, "OnExplorerRestart")
OnExplorerRestart(wParam, lParam, msg, hwnd) {
    global RestartVirtualDesktopAccessorProc
    DllCall(RestartVirtualDesktopAccessorProc, UInt, result)
}

MoveCurrentWindowToDesktop(number) {
	global MoveWindowToDesktopNumberProc, GoToDesktopNumberProc, activeWindowByDesktop
	WinGet, activeHwnd, ID, A
	activeWindowByDesktop[number] := 0 ; Do not activate
	DllCall(MoveWindowToDesktopNumberProc, UInt, activeHwnd, UInt, number)
	DllCall(GoToDesktopNumberProc, UInt, number)
}

GoToPrevDesktop() {
	global GetCurrentDesktopNumberProc, GoToDesktopNumberProc
	current := DllCall(GetCurrentDesktopNumberProc, UInt)
	if (current = 0) {
		GoToDesktopNumber(7)
	} else {
		GoToDesktopNumber(current - 1)
	}
	return
}

GoToNextDesktop() {
	global GetCurrentDesktopNumberProc, GoToDesktopNumberProc
	current := DllCall(GetCurrentDesktopNumberProc, UInt)
	if (current = 7) {
		GoToDesktopNumber(0)
	} else {
		GoToDesktopNumber(current + 1)
	}
	return
}

GoToDesktopNumber(num) {
	global GetCurrentDesktopNumberProc, GoToDesktopNumberProc, IsPinnedWindowProc, activeWindowByDesktop

	; Store the active window of old desktop, if it is not pinned
	WinGet, activeHwnd, ID, A
	current := DllCall(GetCurrentDesktopNumberProc, UInt)
	isPinned := DllCall(IsPinnedWindowProc, UInt, activeHwnd)
	if (isPinned == 0) {
		activeWindowByDesktop[current] := activeHwnd
	}

	; Try to avoid flashing task bar buttons, deactivate the current window if it is not pinned
	if (isPinned != 1) {
		WinActivate, ahk_class Shell_TrayWnd
	}

	; Change desktop
	DllCall(GoToDesktopNumberProc, Int, num)
	return
}

; Windows 10 desktop changes listener
DllCall(RegisterPostMessageHookProc, Int, hwnd, Int, 0x1400 + 30)
OnMessage(0x1400 + 30, "VWMess")
VWMess(wParam, lParam, msg, hwnd) {
	global IsWindowOnCurrentVirtualDesktopProc, IsPinnedWindowProc, activeWindowByDesktop

	desktopNumber := lParam + 1

	; Try to restore active window from memory (if it's still on the desktop and is not pinned)
	WinGet, activeHwnd, ID, A
	isPinned := DllCall(IsPinnedWindowProc, UInt, activeHwnd)
	oldHwnd := activeWindowByDesktop[lParam]
	isOnDesktop := DllCall(IsWindowOnCurrentVirtualDesktopProc, UInt, oldHwnd, Int)
	if (isOnDesktop == 1 && isPinned != 1) {
		WinActivate, ahk_id %oldHwnd%
	}

	; Menu, Tray, Icon, Icons/icon%desktopNumber%.ico

	; When switching to desktop 1, set background pluto.jpg
	; if (lParam == 0) {
		; DllCall("SystemParametersInfo", UInt, 0x14, UInt, 0, Str, "C:\Users\Jarppa\Pictures\Backgrounds\saturn.jpg", UInt, 1)
	; When switching to desktop 2, set background DeskGmail.png
	; } else if (lParam == 1) {
		; DllCall("SystemParametersInfo", UInt, 0x14, UInt, 0, Str, "C:\Users\Jarppa\Pictures\Backgrounds\DeskGmail.png", UInt, 1)
	; When switching to desktop 7 or 8, set background DeskMisc.png
	; } else if (lParam == 2 || lParam == 3) {
		; DllCall("SystemParametersInfo", UInt, 0x14, UInt, 0, Str, "C:\Users\Jarppa\Pictures\Backgrounds\DeskMisc.png", UInt, 1)
	; Other desktops, set background to DeskWork.png
	; } else {
		; DllCall("SystemParametersInfo", UInt, 0x14, UInt, 0, Str, "C:\Users\Jarppa\Pictures\Backgrounds\DeskWork.png", UInt, 1)
	; }
}

; Switching desktops:
; Win + Ctrl + 1 = Switch to desktop 1
*#1::GoToDesktopNumber(0)

; Win + Ctrl + 2 = Switch to desktop 2
*#2::GoToDesktopNumber(1)

; Moving windowes:
; Win + Shift + 1 = Move current window to desktop 1, and go there
+#2::MoveCurrentWindowToDesktop(1)

All functions exported by DLL:

* int GetCurrentDesktopNumber()
* int GetDesktopCount()
* GUID GetDesktopIdByNumber(int number) // Returns zeroed GUID with invalid number found
* int GetDesktopNumber(IVirtualDesktop *pDesktop)
* int GetDesktopNumberById(GUID desktopId)
* GUID GetWindowDesktopId(HWND window)
* int GetWindowDesktopNumber(HWND window)
* int IsWindowOnCurrentVirtualDesktop(HWND window)
* BOOL MoveWindowToDesktopNumber(HWND window, int number)
* void GoToDesktopNumber(int number)
* void RegisterPostMessageHook(HWND listener, int messageOffset)
* void UnregisterPostMessageHook(HWND hwnd)
* int IsPinnedWindow(HWND hwnd) // Returns 1 if pinned, 0 if not pinned, -1 if not valid
* void PinWindow(HWND hwnd)
* void UnPinWindow(HWND hwnd)
* int IsPinnedApp(HWND hwnd) // Returns 1 if pinned, 0 if not pinned, -1 if not valid
* void PinApp(HWND hwnd)
* void UnPinApp(HWND hwnd)
* int IsWindowOnDesktopNumber(HWND window, int number) /
* void RestartVirtualDesktopAccessor() // Call this during taskbar created message

* int ViewIsShownInSwitchers(HWND hwnd) // Is the window shown in Alt+Tab list?
* int ViewIsVisible(HWND hwnd) // Is the window visible?
* HWND ViewGetThumbnailHwnd(HWND hwnd) // Get thumbnail handle for a window, possibly peek preview of Alt+Tab
* void ViewSetFocus(HWND hwnd) // Set focus like Alt+Tab switcher
* HWND ViewGetFocused() // Get focused window thumbnail handle
* void ViewSwitchTo(HWND hwnd) // Switch to window like Alt+Tab switcher
* uint ViewGetByZOrder(HWND *windows, UINT count, BOOL onlySwitcherWindows, BOOL onlyCurrentDesktop) // Get windows in Z-order (NOT alt-tab order)
* uint ViewGetByLastActivationOrder(HWND *windows, UINT count, BOOL onlySwitcherWindows, BOOL onlyCurrentDesktop) // Get windows in alt tab order
* uint ViewGetLastActivationTimestamp(HWND) // Get last activation timestamp

* void EnableKeepMinimized() // Deprecated, does nothing
* void RestoreMinimized() // Deprecated, does nothing

* int CreateVirtualDesktop() // Returns new desktop number, -1 if it fails
* bool RemoveVirtualDesktop(int number, int fallbackDesktop) // returns true if success, otherwise false