lets say i have 2 master page;

master1.master contains contentplaceholder1

master2.master contains contentplaceholder1 and contentplaceholder2

default.aspx contains contentplacehoder1 and contentplaceholder2

if my masterpage is set to master2.master everything works fine but how do i prevent an error when masterpagefile is set to master1.master.

since in my website the masterpage is set dynamically i would like to prevent the error sayin cannot find contentplaceholder 2 when my .aspx file's masterpagefile=master1.master

 I would basically like to have a default contentplaceholder, if it doesnt find that specified contentplaceholder it would insert those items in the defaul contentplaceholder.

 One solution would be to put 2 ContentPlaceHolders in each MasterPage then on PageLoad event choose which PlaceHolder you choose to use.

If MasterPage 1 then set ContentPlaceHolder1.Enabled=True and ContentPlaceHolder2.Enabled=False

If MasterPage 2 then set ContentPlaceHolder1.Enabled=True and ContentPlaceHolder2.Enabled=True

Well that might have been an option, but im using masterpages to control the skin of the website, so since the masterpages are set dynamically and could be made by anyother person. we don't know exactly how many contentplace holder will be required. so is there any way to put contentplaceholders in masterpage programatically to be on the safer side.

Hi,

 Base on your description, you want to create a contentplaceholders in masterpage programatically, right?.

Maybe, you can read this artilce: http://www.codeproject.com/useritems/dynamicmaster.asp
It talks how to creating ContentPlaceHolders and Contents programatically.

Hope it helps.

 The counterpart need to exist in master page. Coud you set a hidden contentpalceholder in master1.mast?