Web application with c# language, Master page

how can 开发者_运维问答i select masterpage2 for my page whereas my page in run time mode and already use masterpage1?

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After a small search on google I found the following article.

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Just so the code is here for anyone who finds this question: (Adapted from @Shaharyar's link)

protected void Page_PreInit(object sender, EventArgs e) 
{ 
 if () { //check for anything you like..

     this.Page.MasterPageFile = "~/General.master"; 
 } 
  else {
     this.Page.MasterPageFile = "~/myMaster.master";
 }
}