How to toggle/switch Windows taskbar from “show” to “auto-hide” (and vice-versa)?

Question

Basically I want to make simple toggle program (that will be mapped to some keyboard shortcut) that set taskbar to auto-hide mode if in normal mode (and conversely, to normal sh

Answer 1

VB "show" and "auto-hide" the Taskbar - Windows 10

I have translated this in VB, which might be usefull for others (Windows 10; should work in 32bit an 64bit):

    Option Explicit On
    Option Strict On
    Imports System.Runtime.InteropServices

    Module WindowsTaskbarSettings

    Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr
    Declare Function SHAppBarMessage Lib "shell32.dll" Alias "SHAppBarMessage" (ByVal dwMessage As Integer, ByRef pData As APPBARDATA) As Integer

    'https://docs.microsoft.com/en-us/windows/win32/api/shellapi/nf-shellapi-shappbarmessage
    'https://docs.microsoft.com/nl-nl/windows/win32/api/shellapi/ns-shellapi-appbardata

    'https://docs.microsoft.com/en-us/windows/win32/shell/abm-getstate 'requires csize to be set
    'https://docs.microsoft.com/en-us/windows/win32/shell/abm-setstate 'requires hwnd and csize to be set

    Structure APPBARDATA
        Dim cbSize As Integer
        Dim hwnd As Long
        Dim uCallbackMessage As Integer '[Delegate]
        Dim uEdge As Integer
        Dim rc As RECT
        Dim lParam As Integer 'message specific, see 
    End Structure

    Structure RECT
        Dim Left As Integer
        Dim Top As Integer
        Dim Right As Integer
        Dim Bottom As Integer
    End Structure

    Public Enum AppBarMessages
        Newx = &H0
        Remove = &H1
        QueryPos = &H2
        SetPos = &H3
        GetState = &H4
        GetTaskBarPos = &H5
        Activate = &H6
        GetAutoHideBar = &H7
        SetAutoHideBar = &H8
        WindowPosChanged = &H9
        SetState = &HA
    End Enum

    Public Enum AppBarStates
        AutoHide = &H1
        AlwaysOnTop = &H2
    End Enum

    Public Sub AutoHide_Toggle()

        If GetTaskbarStateAutoHide() Then
            SetTaskbarState(AppBarStates.AlwaysOnTop)
        Else
            SetTaskbarState(AppBarStates.AutoHide)
        End If
    End Sub

    Public Sub SetTaskbarState(StateOption As AppBarStates)
        'sets the Taskbar State to StateOption (AllwaysOnTop or AutoHide)

        Dim msgData As New APPBARDATA
        msgData.cbSize =  Marshal.SizeOf(msgData)
         'not necessary to use handle of Windows Taskbar, but can be found by
         'msgData.hwnd = CInt(FindWindow("Shell_TrayWnd", ""))

        'Set the State which will be requested
        msgData.lParam = StateOption

        'Ansd send the message to set this state
        SHAppBarMessage(AppBarMessages.SetState, msgData)
        'Remark on my small (1280x800) screen the desktop area remains the same, but on my larger (1080x1920) screen
        'the desktop icons are displaced when autohide is set on !!! Don't understand why (it then thinks the screen is only 800 high)
    End Sub

    Public Function GetTaskbarStateAutoHide() As Boolean
        'true if AutoHide is on, false otherwise

        Dim msgData As New APPBARDATA
        Dim ret As Integer
        msgData.cbSize =  Marshal.SizeOf(msgData)
        ' also here not necessay to find handle to Windows Taskbar

        ret = SHAppBarMessage(AppBarMessages.GetState, msgData)

        GetTaskbarStateAutoHide = CBool(ret And &H1)
    End Function

End Module