Since multiple inheritance is bad (it makes the source more complicated) C# does not provide such a pattern directly. But sometimes it would be helpful to have this ability.
i know i know even though its not allowed and so on, sometime u actualy need it so for the those:
class a {}
class b : a {}
class c : b {}
like in my case i wanted to do this class b : Form (yep the windows.forms) class c : b {}
cause half of the function were identical and with interface u must rewrite them all