Comments by Member 4376970 (Top 1 by date)

@Sergey Alexandrovich Kryukov

I partially disagree with rule
all list elements present in the list are always valid for the selection

not always true

often combos are related each others
changing a previous combo box can made a child selection invalid (was valid in initial context)
in this case I want warns user and give him possibility to cancel the change

this is quite common using and js in web development

I'm studing a solution (quite new to c#)
I think the road is keep combo box current value stored and if necessary reset the value