MasterPage, How-To change it on the fly

surely you can also change your masterPage on the fly. the only thing which has to be done is the following thing:

NOTICE: think about the page cicle!!!!

protected override void OnPreInit(EventArgs e){object tpl = Request.QueryString["Template"];if (tpl == null tpl.ToString() == "Default"){this.MasterPageFile = "~/Templates/Category/Standard.master";}else{this.MasterPageFile = "~/Templates/Category/Sample.master";}}