How to get the tooltip value when hovering the mouse anywhere on the desktop

Question

I'm working on a VB project and I need to capture the tooltip value when hovering over the desktop. Can someone help me figure out how to do this? Is this reversible?

Answer 1

You can use SetWinEventHook :

    Dim procDelegate As WinEventProcDelegate
    Dim hEventHook As IntPtr

In Form1_Load :

    procDelegate = New WinEventProcDelegate(AddressOf WinEventProc)
    hEventHook = SetWinEventHook(EVENT_MIN, EVENT_MAX, IntPtr.Zero, procDelegate, 0, 0, WINEVENT_OUTOFCONTEXT)

Then :

Private Sub WinEventProc(hWinEventHook As IntPtr, eventConst As UInteger, hWnd As IntPtr, idObject As Integer, idChild As Integer, dwEventThread As UInteger, dwmsEventTime As UInteger)
    If (eventConst = EVENT_OBJECT_SHOW) Then
        Dim sb As New StringBuilder(260)
        GetClassName(hWnd, sb, sb.Capacity)
        'Console.WriteLine(sb.ToString())
        If (sb.ToString() = "tooltips_class32") Then
            'Console.Beep(8000, 10)
            Dim sbTooltipText As New StringBuilder(260)
            SendMessage(hWnd, WM_GETTEXT, New IntPtr(260), sbTooltipText)
            Console.WriteLine("Tooltip Text: " & sbTooltipText.ToString())
        End If
    End If   
End Sub
Private Sub Form1_FormClosed(sender As Object, e As FormClosedEventArgs) Handles MyBase.FormClosed
    If (hEventHook <> IntPtr.Zero) Then
        UnhookWinEvent(hEventHook)
    End If
End Sub

With declarations :

    <DllImport("User32.dll", SetLastError:=True, CharSet:=CharSet.Unicode)>
    Private Shared Function SetWinEventHook(eventMin As UInteger, eventMax As UInteger, hmodWinEventProc As IntPtr, pfnWinEventProc As WinEventProcDelegate, idProcess As UInteger, idThread As UInteger, dwFlags As UInteger) As IntPtr
    End Function
    <DllImport("User32.dll", SetLastError:=True, CharSet:=CharSet.Unicode)>
    Public Shared Function UnhookWinEvent(hWinEventHook As IntPtr) As Boolean
    End Function
    Delegate Sub WinEventProcDelegate(hWinEventHook As IntPtr, eventType As UInteger, hwnd As IntPtr, idObject As Integer, idChild As Integer, dwEventThread As UInteger, dwmsEventTime As UInteger)
    Public Const WINEVENT_OUTOFCONTEXT = &H0  ' Events are ASYNC
    Public Const WINEVENT_SKIPOWNTHREAD = &H1  ' Don't call back for events on installer's thread
    Public Const WINEVENT_SKIPOWNPROCESS = &H2  ' Don't call back for events on installer's process
    Public Const WINEVENT_INCONTEXT = &H4  ' Events are SYNC, this causes your dll To be injected into every process
    Public Const EVENT_MIN = &H1
    Public Const EVENT_MAX = &H7FFFFFFF
    ' Does not work on Windows 10
    Public Const EVENT_SYSTEM_SWITCHSTART = &H14
    Public Const EVENT_SYSTEM_SWITCHEND = &H15
    Public Const EVENT_SYSTEM_FOREGROUND = &H3
    Public Const EVENT_OBJECT_CREATE = &H8000  ' hwnd + ID + idChild is created item
    Public Const EVENT_OBJECT_DESTROY = &H8001  ' hwnd + ID + idChild is destroyed item
    Public Const EVENT_OBJECT_SHOW = &H8002  ' hwnd + ID + idChild is shown item
    Public Const EVENT_OBJECT_HIDE = &H8003  ' hwnd + ID + idChild is hidden item
    Public Const EVENT_OBJECT_REORDER = &H8004  ' hwnd + ID + idChild is parent of zordering children
    Public Const EVENT_OBJECT_FOCUS = &H8005  ' hwnd + ID + idChild is focused item
    Public Const EVENT_OBJECT_SELECTION = &H8006  ' hwnd + ID + idChild is selected item (if only one), or idChild is OBJID_WINDOW if complex
    Public Const EVENT_OBJECT_SELECTIONADD = &H8007  ' hwnd + ID + idChild is item added
    Public Const EVENT_OBJECT_SELECTIONREMOVE = &H8008  ' hwnd + ID + idChild is item removed
    Public Const EVENT_OBJECT_SELECTIONWITHIN = &H8009  ' hwnd + ID + idChild is parent of changed selected items
    Public Const EVENT_OBJECT_STATECHANGE = &H800A  ' hwnd + ID + idChild is item w/ state change
    Public Const EVENT_OBJECT_LOCATIONCHANGE = &H800B  ' hwnd + ID + idChild is moved/sized item
    Public Const EVENT_OBJECT_NAMECHANGE = &H800C  ' hwnd + ID + idChild is item w/ name change
    Public Const EVENT_OBJECT_DESCRIPTIONCHANGE = &H800D  ' hwnd + ID + idChild is item w/ desc change
    Public Const EVENT_OBJECT_VALUECHANGE = &H800E  ' hwnd + ID + idChild is item w/ value change
    Public Const EVENT_OBJECT_PARENTCHANGE = &H800F  ' hwnd + ID + idChild is item w/ new parent
    Public Const EVENT_OBJECT_HELPCHANGE = &H8010  ' hwnd + ID + idChild is item w/ help change
    Public Const EVENT_OBJECT_DEFACTIONCHANGE = &H8011  ' hwnd + ID + idChild is item w/ def action change
    Public Const EVENT_OBJECT_ACCELERATORCHANGE = &H8012  ' hwnd + ID + idChild is item w/ keybd accel change
    Public Const EVENT_OBJECT_INVOKED = &H8013  ' hwnd + ID + idChild is item invoked
    Public Const EVENT_OBJECT_TEXTSELECTIONCHANGED = &H8014  ' hwnd + ID + idChild is item w? test selection change
    Public Const EVENT_OBJECT_CONTENTSCROLLED = &H8015
    Public Const EVENT_SYSTEM_ARRANGMENTPREVIEW = &H8016
    Public Const EVENT_OBJECT_CLOAKED = &H8017
    Public Const EVENT_OBJECT_UNCLOAKED = &H8018
    Public Const EVENT_OBJECT_LIVEREGIONCHANGED = &H8019
    Public Const EVENT_OBJECT_HOSTEDOBJECTSINVALIDATED = &H8020
    Public Const EVENT_OBJECT_DRAGSTART = &H8021
    Public Const EVENT_OBJECT_DRAGCANCEL = &H8022
    Public Const EVENT_OBJECT_DRAGCOMPLETE = &H8023
    Public Const EVENT_OBJECT_DRAGENTER = &H8024
    Public Const EVENT_OBJECT_DRAGLEAVE = &H8025
    Public Const EVENT_OBJECT_DRAGDROPPED = &H8026
    Public Const EVENT_OBJECT_IME_SHOW = &H8027
    Public Const EVENT_OBJECT_IME_HIDE = &H8028
    Public Const EVENT_OBJECT_IME_CHANGE = &H8029
    Public Const EVENT_OBJECT_TEXTEDIT_CONVERSIONTARGETCHANGED = &H8030
    Public Const EVENT_OBJECT_END = &H80FF
    Public Const OBJID_WINDOW = &H0
    Public Const OBJID_SYSMENU = &HFFFFFFFF
    Public Const OBJID_TITLEBAR = &HFFFFFFFE
    Public Const OBJID_MENU = &HFFFFFFFD
    Public Const OBJID_CLIENT = &HFFFFFFFC
    Public Const OBJID_VSCROLL = &HFFFFFFFB
    Public Const OBJID_HSCROLL = &HFFFFFFFA
    Public Const OBJID_SIZEGRIP = &HFFFFFFF9
    Public Const OBJID_CARET = &HFFFFFFF8
    Public Const OBJID_CURSOR = &HFFFFFFF7
    Public Const OBJID_ALERT = &HFFFFFFF6
    Public Const OBJID_SOUND = &HFFFFFFF5
    Public Const OBJID_QUERYCLASSNAMEIDX = &HFFFFFFF4
    Public Const OBJID_NATIVEOM = &HFFFFFFF0
    <DllImport("User32.dll", SetLastError:=True, CharSet:=CharSet.Unicode)>
    Public Shared Function GetClassName(hWnd As IntPtr, lpClassName As StringBuilder, ByVal nMaxCount As Integer) As Integer
    End Function
    <DllImport("User32.dll", SetLastError:=True, CharSet:=CharSet.Unicode)>
    Public Shared Function SendMessage(hWnd As IntPtr, Msg As Integer, wParam As IntPtr, lParam As StringBuilder) As IntPtr
    End Function
    Public Const WM_GETTEXT As Integer = &HD