The AccessibleObjectFromWindow function retrieves the address of the specified interface to the object associated with the given window.
C# Signature:
[DllImport("oleacc.dll")]
internal static extern int AccessibleObjectFromWindow(
IntPtr hwnd,
uint id,
ref Guid iid,
[In, Out, MarshalAs(UnmanagedType.IUnknown)] ref object ppvObject);
VB .Net Signature:
Private Declare Function AccessibleObjectFromWindow Lib "oleacc" (ByVal Hwnd As Int32, _
ByVal dwId As Int32, _
ByRef riid As Guid, _
<MarshalAs(UnmanagedType.IUnknown)> ByRef ppvObject As Object) As Int32
User-Defined Types:
None.
Notes:
None.
Tips & Tricks:
Please add some!
Sample Code:
Visual Basic
Private Declare Function AccessibleObjectFromWindow Lib "oleacc" (ByVal Hwnd As Int32, _
ByVal dwId As Int32, _
ByRef riid As Guid, _
<MarshalAs(UnmanagedType.IUnknown)> ByRef ppvObject As Object) As Int32
Declare Function GetForegroundWindow Lib "user32" () As Int32
Private Sub Form2_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim varChild As Accessibility.IAccessible
Dim hWnd As Int32 = GetForegroundWindow()
Dim ID As Int32 = 0
Dim IID_IAcce As Guid = New Guid("618736E0-3C3D-11CF-810C-00AA00389B71")
Dim aaVal As Int32 = AccessibleObjectFromWindow(hWnd, ID, IID_IAcce, varChild)
End Sub
C#
internal enum OBJID : uint
{
WINDOW = 0x00000000,
SYSMENU = 0xFFFFFFFF,
TITLEBAR = 0xFFFFFFFE,
MENU = 0xFFFFFFFD,
CLIENT = 0xFFFFFFFC,
VSCROLL = 0xFFFFFFFB,
HSCROLL = 0xFFFFFFFA,
SIZEGRIP = 0xFFFFFFF9,
CARET = 0xFFFFFFF8,
CURSOR = 0xFFFFFFF7,
ALERT = 0xFFFFFFF6,
SOUND = 0xFFFFFFF5,
}
Guid guid = new Guid("{618736E0-3C3D-11CF-810C-00AA00389B71}");
object obj = null;
int retVal = AccessibleObjectFromWindow(hwnd, (uint)OBJID.WINDOW, ref guid, ref obj);
accessible = (IAccessible) obj;
Alternative Managed API:
The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides a SystemAccessibleObject class to access accessible objects, that can be instantiated from a window.
