private void WmGetObject(ref Message m)
{
if (m.LParam == (IntPtr)NativeMethods.UiaRootObjectId)
{
AccessibleObject uiaProvider = GetChildAccessibleObject(_childWindowType);
// If the requested object identifier is UiaRootObjectId,
// we should return an UI Automation provider using the UiaReturnRawElementProvider function.
InternalAccessibleObject internalAccessibleObject = new InternalAccessibleObject(uiaProvider);
m.Result = UiaCore.UiaReturnRawElementProvider(
new HandleRef(this, Handle),
m.WParam,
m.LParam,
internalAccessibleObject);
return;
}
// See "How to Handle WM_GETOBJECT" in MSDN
//
if (unchecked ((int)(long)m.LParam) == OBJID.CLIENT)
{
// Get the IAccessible GUID
//
Guid IID_IAccessible = new Guid(NativeMethods.uuid_IAccessible);
// Get an Lresult for the accessibility Object for this control
//
IntPtr punkAcc;
try
{
AccessibleObject wfAccessibleObject = null;
UiaCore.IAccessibleInternal iacc = null;
if (_accessibilityObject is null)
{
wfAccessibleObject = GetChildAccessibleObject(_childWindowType);
_accessibilityObject = new InternalAccessibleObject(wfAccessibleObject);
}
iacc = (UiaCore.IAccessibleInternal)_accessibilityObject;
// Obtain the Lresult
//
punkAcc = Marshal.GetIUnknownForObject(iacc);
try
{
m.Result = Oleacc.LresultFromObject(ref IID_IAccessible, m.WParam, new HandleRef(this, punkAcc));
}
finally
{
Marshal.Release(punkAcc);
}
}
catch (Exception e)
{
throw new InvalidOperationException(SR.RichControlLresult, e);
}
}
else
{ // m.lparam != OBJID_CLIENT, so do default message processing
DefWndProc(ref m);
}
}
private void WmGetObject(ref Message m)
{
if (m.LParam == (IntPtr)NativeMethods.UiaRootObjectId &&
// Managed UIAutomation providers are supplied for child list windows but not for the child edit window.
// Child list accessibility object provides all necessary patterns and UIAutomation notifications,
// so there is no need to native provider supplement.
// Child edit accessibility object has only partial support of edit box accessibility, most of the patterns
// and notifications for child edit window are supplied by native providers, so here is no need to
// override root UIA object for child edit window.
(_childWindowType == ChildWindowType.ListBox || _childWindowType == ChildWindowType.DropDownList))
{
AccessibleObject uiaProvider = GetChildAccessibleObject(_childWindowType);
// If the requested object identifier is UiaRootObjectId,
// we should return an UI Automation provider using the UiaReturnRawElementProvider function.
InternalAccessibleObject internalAccessibleObject = new InternalAccessibleObject(uiaProvider);
m.Result = UiaCore.UiaReturnRawElementProvider(
new HandleRef(this, Handle),
m.WParam,
m.LParam,
internalAccessibleObject);
return;
}
// See "How to Handle WM_GETOBJECT" in MSDN
//
if (unchecked ((int)(long)m.LParam) == OBJID.CLIENT)
{
// Get the IAccessible GUID
//
Guid IID_IAccessible = new Guid(NativeMethods.uuid_IAccessible);
// Get an Lresult for the accessibility Object for this control
//
IntPtr punkAcc;
try
{
AccessibleObject wfAccessibleObject = null;
UiaCore.IAccessibleInternal iacc = null;
if (_accessibilityObject is null)
{
wfAccessibleObject = GetChildAccessibleObject(_childWindowType);
_accessibilityObject = new InternalAccessibleObject(wfAccessibleObject);
}
iacc = (UiaCore.IAccessibleInternal)_accessibilityObject;
// Obtain the Lresult
//
punkAcc = Marshal.GetIUnknownForObject(iacc);
try
{
m.Result = Oleacc.LresultFromObject(ref IID_IAccessible, m.WParam, new HandleRef(this, punkAcc));
}
finally
{
Marshal.Release(punkAcc);
}
}
catch (Exception e)
{
throw new InvalidOperationException(SR.RichControlLresult, e);
}
}
else
{ // m.lparam != OBJID_CLIENT, so do default message processing
DefWndProc(ref m);
}
}
