How do I detect if a scriptmanager is on the page?

Mid*_*one 4 asp.net scriptmanager

How do I detect if a scriptmanager is loaded on a page? Some aspx pages have it and others don't and I need a user control to understand this so that it can either load it if needed and also for dealing with viewstate.

bdu*_*kes 8

呼叫ScriptManager.GetCurrent(page),null如果ScriptManger页面上没有,将返回.