Set Master page for Publishing sites for publishing page

Change master page for Publlishing site .

SPSite curSite = new SPSite(http://MySERVER:1000/); 
SPWeb objweb = curSite.OpenWeb(strWeb);
//Besure to check the path of the master page.

Uri masterUri = new Uri("http://MySERVER:1000/" + /_catalogs/masterpage/My_MasterPage_Blank_right_1.0.master");

objweb.CustomMasterUrl = masterUri.AbsolutePath;
objweb.AllowUnsafeUpdates = true;

objweb.Update();
objweb.AllowUnsafeUpdates = false;