With autopostback property set to true, there will be two hidden variable in
your form __EVENTTARGET and __EVENTARGUMENT which you can access in
Page_Load event to get the control name which caused the postback.
__EVENTTARGET will have the object which fired the post back event.
Both __EVENTTARGET and __EVENTARGUMENT return null.
I read on the web that some controls reset the value of these hidden fields.
Is there a way to overcome this problem or other ways to determine the
control that submitted the form?