void LoadPreviousPageReference ()
{
if (_requestValueCollection != null) {
string prevPage = _requestValueCollection [PreviousPageID];
if (prevPage != null) {
previousPage = (Page) PageParser.GetCompiledPageInstance (prevPage, Server.MapPath (prevPage), Context);
previousPage.ProcessCrossPagePostBack (_context);
} else {
previousPage = _context.LastPage;
}
}
_context.LastPage = this;
}