VK_PRIOR key not working

using WebBrowser Control to display a PPT file.

With Office 2007 this is successful, but with Office 2010, the page down key (VK_PRIOR) does not work.

This code for click previous does not work with Office 2010, but works with Office 2007:

Private Sub btnPREV_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPREV.Click
            If docType = DocumentType.PPT Then
                If hndl = IntPtr.Zero Then
                    GetHandles()
                End If
                NativeMethods.PostMessage(hndl, WM_KEYDOWN, VK_PRIOR, IntPtr.Zero)
                NativeMethods.PostMessage(hndl, WM_KEYUP, VK_PRIOR, IntPtr.Zero)
            End If
    End Sub

This code for click next works with both Office 2007 and 2010:

Private Sub BtnNEXT_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNEXT.Click
            If docType = DocumentType.PPT Then
                If hndl =开发者_高级运维 IntPtr.Zero Then
                    GetHandles()
                End If
                NativeMethods.PostMessage(hndl, WM_KEYDOWN, VK_NEXT, IntPtr.Zero)
                NativeMethods.PostMessage(hndl, WM_KEYUP, VK_NEXT, IntPtr.Zero)
            End If
    End Sub

The solution is found:

WebBrowser1 is the object of the WebBrowser Class.

WebBrowser1.Focus()
btnBACK.Focus()
WebBrowser1.Focus()
SendKeys.Send("{UP}")

That's it. The "previous" click starts working, since the Page Up event is fired.