Unable to play videos in wxWidgets sample Media player?

Question

I am using wxWidgets samples code for media player. Here first we need to select the file from the wxFileDialog and on clicking play button it will play the video.

But I don't want to select the file from the wxFileDialog, I am passing the video path in DoOpenFile(path, bNewPage); and then clicking on play button then the video is not playing.

void wxMediaPlayerFrame::OnPlay(wxCommandEvent& WXUNUSED(event))
{
    DoOpenFile(_("D:\\myvideo.mp4"), false);
    wxMediaPlayerNotebookPage* currentpage = (wxMediaPlayerNotebookPage*)m_notebook->GetCurrentPage();

 ....
 ....
 ....
}