wxWidgets Transparent wxTextCtrl

I'm trying to create a custom transparent wxTextCtrl by driving from it and drawing the text myself as follow:

BEGIN_EVENT_TABLE(TextLayer, wxTextCtrl)
    EVT_PAINT(TextLayer::OnPaint)
    EVT_ERASE_BACKGROUND(TextLayer::OnEraseBackground)
END_EVENT_TABLE()

void TextLayer::OnEraseBackground(wxEraseEvent& event) {}
void TextLayer::OnPaint(wxPaintEvent & evt)
{
    wxAutoBufferedPaintDC  dc(this);
    PrepareDC(dc);

    wxGraphicsContext *gc = wxGraphicsContext::Create( dc );

    if(gc)
    {
        dc.SetFont(GetFont());
        dc.SetTextForeground(GetForegroundColour());
        auto a = GetValue();
        dc.DrawText(GetValue(), 0, 0);
        delete gc;
    }
}

but it's not working , it's not transparent , how I'm supposed to do it correctly?