[RESOLVED] What declaration for AccessibleObjectFromEvent?

[TT(n)]

Does anyone know of a working declaration for the API "AccessibleObjectFromEvent"? Or a good .net equivelant?

I've spent so much time getting the other main Accessible API to work on .NET, that I'm hoping to start with a good declare on this one.
I've built a really good narrator, for totally blind people so that they can interface and use the computer in a substantial way. The innovation is a static mouse that controls category input, rather than free mouse movement, and the middle wheel selectes items of that category.
But I need the last access API for events and voice feedback when the event occurs.


I'm guessing it's something like this, according to what works for the other API:

Private Declare Function apiAccessibleObjectFromEvent Lib "oleacc" Alias "AccessibleObjectFromEvent" (ByVal hwnd As Int32, ByVal dwObjectID As Int32, ByVal dwChildID As Int32, ByRef ppacc As Global.Accessibility.IAccessible, ByRef pvarChild As Object) As Int32

In case anyone is interested in the other API's, I've included a project zip file, with:
AccessibleObjectFromWindow, AccessibleChildren, & AccessibleObjectFromPoint.
This is loosely based upon microsoft AAccess example written in vb6, available as an online download. I've have not seen a .NET example online, so it might proove useful for someone.

Option Strict On
Option Explicit On
Module Accessibility
    Const CHILDID_SELF As Int32 = 0
    Const CHILDID_1 As Int32 = 1
    Const OBJID_CLIENT As Int32 = &HFFFFFFFC
    Const OBJID_CARET As Int32 = &HFFFFFFF8
    Const OBJID_CURSOR As Int32 = &HFFFFFFF7
    Const OBJID_MENU As Int32 = &HFFFFFFFD
    Const OBJID_NATIVEOM As Int32 = &HFFFFFFF0
    Const OBJID_SYSMENU As Int32 = &HFFFFFFFF
    Const OBJID_TITLEBAR As Int32 = &HFFFFFFFE
    Const OBJID_WINDOW As Int32 = 0
    Const OBJID_VSCROLL As Int32 = &HFFFFFFFB
    Const OBJID_HSCROLL As Int32 = &HFFFFFFFA
    Const OBJID_SIZEGRIP As Int32 = &HFFFFFFF9
    Const OBJID_ALERT As Int32 = &HFFFFFFF6
    Const OBJID_SOUND As Int32 = &HFFFFFFF5
    Public Structure POINTAPI
        Public x, y As Int32
    End Structure
    Public Structure RECT
        Public rLeft, rTop, rRight, rBottom As Int32
    End Structure
    Public Structure ACCOBJINFO
        Public Text, Value, DefaultAction, KeyShortcut, Description, Help As String
        Public State, Selection As Double
        Public Parent As Global.Accessibility.IAccessible
        Public Position As POINTAPI
        Public Size As Size
        Public ItemPosition As POINTAPI
        Public ItemSize As Size
    End Structure
    ' Private Declare Function apiAccessibleObjectFromEvent Lib "oleacc" Alias "AccessibleObjectFromEvent" (ByVal hwnd As Int32, ByVal dwObjectID As Int32, ByVal dwChildID As Int32, ByRef ppacc As Global.Accessibility.IAccessible, ByRef pvarChild As Object) As Int32
    Private Declare Function apiAccessibleObjectFromWindow Lib "oleacc" Alias "AccessibleObjectFromWindow" (ByVal Hwnd As Int32, ByVal dwId As Int32, ByRef riid As Guid, ByRef ppacc As Global.Accessibility.IAccessible) As Int32
    Private Declare Function apiAccessibleChildren Lib "oleacc" Alias "AccessibleChildren" (ByVal paccContainer As Global.Accessibility.IAccessible, ByVal iChildStart As Int32, ByVal cChildren As Int32, <System.Runtime.InteropServices.[Out]()> ByVal rgvarChildren() As Object, ByRef pcObtained As Int32) As UInteger
    Private Declare Function apiAccessibleObjectFromPoint Lib "oleacc" Alias "AccessibleObjectFromPoint" (ByVal pt As POINTAPI, ByRef ppacc As Global.Accessibility.IAccessible, ByRef pvarChild As Object) As Int32
    Private Declare Function apiGetCursorPos Lib "user32" Alias "GetCursorPos" (ByRef lpPoint As POINTAPI) As Boolean
    Private Declare Function apiGetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hWnd As Int32, ByVal lpString As String, ByVal cch As Int32) As Int32
    Private Declare Function apiGetWindowTextLength Lib "user32" Alias "GetWindowTextLengthA" (ByVal hWnd As Int32) As Int32
    Public Declare Function apiFindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Int32, ByVal hWnd2 As Int32, ByVal lpsz1 As String, ByVal lpsz2 As String) As Int32
    Private IID_IAcce As Guid = New Guid("618736E0-3C3D-11CF-810C-00AA00389B71")
    Private IID_IDispatch As Guid = New Guid("00020424-0000-0000-C000-000000000046")

    Public Function GetObjectFromPoint(ByVal pt As POINTAPI) As ACCOBJINFO
        On Error Resume Next : GetObjectFromPoint = Nothing ' Not all the acc properties will work  with all the returned objects.
        Dim accObj As Global.Accessibility.IAccessible = Nothing
        Dim objChild As Object = Nothing
        Dim objInf As New ACCOBJINFO
        If pt.x = 0 AndAlso pt.y = 0 Then apiGetCursorPos(pt) ' Get the cursor position where the mouse was clicked.
        apiAccessibleObjectFromPoint(pt, accObj, objChild) ' Get the IAccessible interface of the object located under the cursor position.
        GetObjectFromPoint.Text = accObj.accName(objChild)
        GetObjectFromPoint.Value = accObj.accValue(objChild)
        GetObjectFromPoint.DefaultAction = accObj.accDefaultAction(objChild)
        GetObjectFromPoint.KeyShortcut = accObj.accKeyboardShortcut(objChild)
        GetObjectFromPoint.Description = accObj.accDescription(objChild)
        GetObjectFromPoint.Help = accObj.accHelp(objChild)
        GetObjectFromPoint.State = CDbl(accObj.accState(objChild))
        GetObjectFromPoint.Selection = CDbl(accObj.accSelection())
        GetObjectFromPoint.Parent = CType(accObj.accParent(), IAccessible)
        accObj.accLocation(GetObjectFromPoint.Position.x, GetObjectFromPoint.Position.y, 0, 0, 0)
        accObj.accLocation(0, 0, GetObjectFromPoint.Size.Width, GetObjectFromPoint.Size.Height, 0)
        accObj.accLocation(GetObjectFromPoint.ItemPosition.x, GetObjectFromPoint.ItemPosition.y, 0, 0, objChild)
        accObj.accLocation(0, 0, GetObjectFromPoint.ItemSize.Width, GetObjectFromPoint.ItemSize.Height, objChild)
        accObj = Nothing : objChild = Nothing
    End Function

    Public Function GetFormControls(ByVal hwnd As Int32) As ACCOBJINFO() 'This is loosely based upon microsoft AAccess example written in vb6, available as an online download.  No .NET version known though, except this one
        On Error Resume Next
        Dim numCtrls, numCtrlsRet As Int32
        Dim accObj As Global.Accessibility.IAccessible = Nothing
        Dim newAccObj As Global.Accessibility.IAccessible = Nothing
        Dim objChildren() As Global.Accessibility.IAccessible = Nothing
        Dim objControls() As Global.Accessibility.IAccessible = Nothing
        Dim objArray As ACCOBJINFO()
        Dim wText As String = GetWindowText(hwnd)
        If wText = "" Then Return Nothing
        apiAccessibleObjectFromWindow(hwnd, OBJID_WINDOW, IID_IAcce, accObj) ' Get forms IAccessible interface
        numCtrls = accObj.accChildCount 'set count to children count
        ReDim objChildren(numCtrls - 1) 'Array length is the number of children parented by object
        apiAccessibleChildren(accObj, 0, numCtrls, objChildren, numCtrlsRet) ' Get all children
        For i As Int32 = 0 To numCtrlsRet - 1 ' Get main client object , since the previous call got all system info etc
            If objChildren(i).accName = wText Then
                newAccObj = objChildren(i)
                numCtrls = newAccObj.accChildCount
            End If 'Could get titlebar stuff here
            ' Dim left, top, width, height As Int32
            ' objChildren(i).accLocation(left, top, width, height)
            ' MessageBox.Show( left.ToString & " " & top.ToString & " " & width.ToString & " " & height.ToString)
            ' DrawRectangle(left, top, width, height)
        Next
        ReDim objControls(numCtrls - 1) 'Re dimension, so that we can actually get children controls of the forms IAccessible interface
        apiAccessibleChildren(newAccObj, 0, numCtrls, objControls, numCtrlsRet) 'Get controls
        ReDim objArray(numCtrlsRet - 1)
        For i As Int32 = 0 To numCtrlsRet - 1 'Gather properties of the returned IAccessible objects
            objArray(i).Text = objControls(i).accName
            objArray(i).Value = objControls(i).accValue
            objArray(i).DefaultAction = objControls(i).accDefaultAction
            objArray(i).KeyShortcut = objControls(i).accKeyboardShortcut
            objArray(i).Description = objControls(i).accDescription
            objArray(i).Help = objControls(i).accHelp
            objArray(i).State = CDbl(objControls(i).accState)
            objArray(i).Selection = CDbl(objControls(i).accSelection)
            objArray(i).Parent = CType(objControls(i).accParent, IAccessible)
            objControls(i).accLocation(objArray(i).Position.x, objArray(i).Position.y, 0, 0, 0)
            objControls(i).accLocation(0, 0, objArray(i).Size.Width, objArray(i).Size.Height, 0)
        Next
        accObj = Nothing : newAccObj = Nothing : objChildren = Nothing : objControls = Nothing
        Return objArray 'Return with an array of controls, containing property information of each control
    End Function

    Private Function GetWindowText(ByVal hwnd As Int32) As String
        On Error Resume Next
        Dim tLength, rValue As Int32 : GetWindowText = "" 'Initialize string for text name
        tLength = apiGetWindowTextLength(hwnd) + 4 'Get length
        GetWindowText = GetWindowText.PadLeft(tLength) '''''Pad with buffer
        rValue = apiGetWindowText(hwnd, GetWindowText, tLength) 'Get text
        GetWindowText = GetWindowText.Substring(0, rValue) 'Strip buffer
    End Function

End Module