//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
#region Private Methods
// call this method before allowing access to any TextPattern properties or methods.
// it ensures that we have an ITextDocument pointer to the richedit control.
private void EnsureTextDocument()
{
// if we don't have a document pointer yet then get one by sending richedit a WM_GETOBJECT message
// with object id asking for the native OM.
if (_document == null)
{
object obj = null;
if (UnsafeNativeMethods.AccessibleObjectFromWindow(WindowHandle, NativeMethods.OBJID_NATIVEOM, ref UnsafeNativeMethods.IID_IDispatch, ref obj) != NativeMethods.S_OK)
{
throw new System.NotImplementedException(SR.Get(SRID.NoITextDocumentFromRichEdit));
}
// review: - alexsn - This is temp solution which will prevent exception in the case
// when we cannot obtain the ITextDocument from a RichEdit control
// The direct cast does not work for RichEdit20w controls used in MS Office
// Susia will do the real fix
_document = obj as ITextDocument;
if (_document == null)
{
// review: proper exception?
throw new System.NotImplementedException(SR.Get(SRID.NoITextDocumentFromRichEdit));
}
}
}
public static IAccessible GetAccessibleObject(IntPtr hWnd)
{
try {
Guid guid = new Guid("618736e0-3c3d-11cf-810c-00aa00389b71");
Object instance = null;
const int OBJID_WINDOW = 0x0;
int hResult = UnsafeNativeMethods.AccessibleObjectFromWindow(hWnd, OBJID_WINDOW, ref guid, ref instance);
if (hResult != 0 || instance == null)
{
return(null);
}
return(instance as IAccessible);
}
catch {
return(null);
}
}
